diff --git a/ui/models/account.cpp b/ui/models/account.cpp
index a60315c..00dd6b2 100644
--- a/ui/models/account.cpp
+++ b/ui/models/account.cpp
@@ -17,6 +17,8 @@
  */
 
 #include "account.h"
+#include "contact.h"
+#include "reference.h"
 #include <QDebug>
 
 Models::Account::Account(const QMap<QString, QVariant>& data, Models::Item* parentItem):
@@ -267,4 +269,3 @@ void Models::Account::setPasswordType(unsigned int pt)
 {
     setPasswordType(Shared::Global::fromInt<Shared::AccountPassword>(pt));
 }
-
diff --git a/ui/models/account.h b/ui/models/account.h
index d2bb79f..2563382 100644
--- a/ui/models/account.h
+++ b/ui/models/account.h
@@ -28,6 +28,9 @@
 #include <QIcon>
 
 namespace Models {
+    class Contact;
+    class Reference;
+    
     class Account : public Item {
         Q_OBJECT
     public:
diff --git a/ui/models/contact.cpp b/ui/models/contact.cpp
index 9cd011a..cc3caba 100644
--- a/ui/models/contact.cpp
+++ b/ui/models/contact.cpp
@@ -17,10 +17,11 @@
  */
 
 #include "contact.h"
+#include "account.h"
 
 #include <QDebug>
 
-Models::Contact::Contact(const QString& p_jid ,const QMap<QString, QVariant> &data, Item *parentItem):
+Models::Contact::Contact(const Account* acc, const QString& p_jid ,const QMap<QString, QVariant> &data, Item *parentItem):
     Item(Item::contact, data, parentItem),
     jid(p_jid),
     availability(Shared::Availability::offline),
@@ -30,7 +31,8 @@ Models::Contact::Contact(const QString& p_jid ,const QMap<QString, QVariant> &da
     messages(),
     childMessages(0),
     status(),
-    avatarPath()
+    avatarPath(),
+    account(acc)
 {
     QMap<QString, QVariant>::const_iterator itr = data.find("state");
     if (itr != data.end()) {
@@ -368,7 +370,8 @@ Models::Contact::Contact(const Models::Contact& other):
     state(other.state),
     presences(),
     messages(other.messages),
-    childMessages(0)
+    childMessages(0),
+    account(other.account)
 {
     for (const Presence* pres : other.presences) {
         Presence* pCopy = new Presence(*pres);
@@ -415,3 +418,9 @@ void Models::Contact::setAvatarState(unsigned int p_state)
         qDebug() << "An attempt to set invalid avatar state" << p_state << "to the contact" << jid << ", skipping";
     }
 }
+
+const Models::Account * Models::Contact::getParentAccount() const
+{
+    return account;
+}
+
diff --git a/ui/models/contact.h b/ui/models/contact.h
index eb2be6b..39418ae 100644
--- a/ui/models/contact.h
+++ b/ui/models/contact.h
@@ -31,13 +31,14 @@
 #include <deque>
 
 namespace Models {
+class Account;
     
 class Contact : public Item
 {
     Q_OBJECT
 public:
     typedef std::deque<Shared::Message> Messages;
-    Contact(const QString& p_jid, const QMap<QString, QVariant> &data, Item *parentItem = 0);
+    Contact(const Account* acc, const QString& p_jid, const QMap<QString, QVariant> &data, Item *parentItem = 0);
     Contact(const Contact& other);
     ~Contact();
     
@@ -72,6 +73,7 @@ public:
 protected:
     void _removeChild(int index) override;
     bool columnInvolvedInDisplay(int col) override;
+    const Account* getParentAccount() const override;
     
 protected slots:
     void refresh();
@@ -98,6 +100,7 @@ private:
     unsigned int childMessages;
     QString status;
     QString avatarPath;
+    const Account* account;
 };
 
 }
diff --git a/ui/models/group.cpp b/ui/models/group.cpp
index 76dc03e..5cf411b 100644
--- a/ui/models/group.cpp
+++ b/ui/models/group.cpp
@@ -18,6 +18,7 @@
 
 #include "group.h"
 #include "contact.h"
+#include "reference.h"
 
 Models::Group::Group(const QMap<QString, QVariant>& data, Models::Item* parentItem):
     Item(group, data, parentItem),
@@ -103,16 +104,3 @@ unsigned int Models::Group::getOnlineContacts() const
     
     return amount;
 }
-
-bool Models::Group::hasContact(const QString& jid) const
-{
-    for (Models::Item* item : childItems) {
-        if (item->type == Item::contact) {
-            const Contact* cnt = static_cast<const Contact*>(item);
-            if (cnt->getJid() == jid) {
-                return true;
-            }
-        }
-    }
-    return false;
-}
diff --git a/ui/models/group.h b/ui/models/group.h
index c2f4bfe..7343b63 100644
--- a/ui/models/group.h
+++ b/ui/models/group.h
@@ -23,6 +23,8 @@
 
 namespace Models {
 
+class Contact;
+    
 class Group : public Models::Item
 {
     Q_OBJECT
@@ -36,8 +38,6 @@ public:
     
     unsigned int getUnreadMessages() const;
     unsigned int getOnlineContacts() const;
-    
-    bool hasContact(const QString& jid) const;
 
 protected:
     void _removeChild(int index) override;
diff --git a/ui/models/item.cpp b/ui/models/item.cpp
index b653702..566c26a 100644
--- a/ui/models/item.cpp
+++ b/ui/models/item.cpp
@@ -18,6 +18,8 @@
 
 #include "item.h"
 #include "account.h"
+#include "reference.h"
+#include "contact.h"
 
 #include <QDebug>
 
@@ -46,11 +48,16 @@ Models::Item::Item(const Models::Item& other):
 
 Models::Item::~Item()
 {
-    std::deque<Item*>::const_iterator itr = childItems.begin();
-    std::deque<Item*>::const_iterator end = childItems.end();
+    for (Reference* ref : references) {
+        Item* parent = ref->parentItem();
+        if (parent != nullptr) {
+            parent->removeChild(ref->row());
+        }
+        delete ref;
+    }
     
-    for (;itr != end; ++itr) {
-        delete (*itr);
+    for (Item* child : childItems) {
+        delete child;
     }
 }
 
@@ -67,18 +74,26 @@ void Models::Item::appendChild(Models::Item* child)
     bool moving = false;
     int newRow = 0;
     std::deque<Item*>::const_iterator before = childItems.begin();
+    Type ct = child->type;
+    if (ct == reference) {
+        ct = static_cast<Reference*>(child)->dereference()->type;
+    }
     while (before != childItems.end()) {
         Item* bfr = *before;
-        if (bfr->type > child->type) {
+        Type bt = bfr->type;
+        if (bt == reference) {
+            bt = static_cast<Reference*>(bfr)->dereference()->type;
+        }
+        if (bt > ct) {
             break;
-        } else if (bfr->type == child->type && bfr->getDisplayedName() > child->getDisplayedName()) {
+        } else if (bt == ct && bfr->getDisplayedName() > child->getDisplayedName()) {
             break;
         }
         newRow++;
         before++;
     }
     
-    if (child->parent != 0) {
+    if (child->parent != nullptr) {
         int oldRow = child->row();
         moving = true;
         emit childIsAboutToBeMoved(child->parent, oldRow, oldRow, this, newRow);
@@ -116,7 +131,7 @@ int Models::Item::childCount() const
 
 int Models::Item::row() const
 {
-    if (parent != 0) {
+    if (parent != nullptr) {
         std::deque<Item*>::const_iterator itr = parent->childItems.begin();
         std::deque<Item*>::const_iterator end = parent->childItems.end();
         
@@ -127,7 +142,7 @@ int Models::Item::row() const
         }
     }
     
-    return 0;       //TODO not sure how it helps, i copy-pasted it from the example
+    return -1;       //TODO not sure how it helps
 }
 
 Models::Item * Models::Item::parentItem()
@@ -178,13 +193,13 @@ void Models::Item::_removeChild(int index)
     QObject::disconnect(child, &Item::childMoved, this, &Item::childMoved);
     
     childItems.erase(childItems.begin() + index);
-    child->parent = 0;
+    child->parent = nullptr;
 }
 
 
 void Models::Item::changed(int col)
 {
-    if (parent != 0) {
+    if (parent != nullptr) {
         emit childChanged(this, row(), col);
     }
 }
@@ -197,21 +212,21 @@ void Models::Item::toOfflineState()
     }
 }
 
-const Models::Item * Models::Item::getParentAccount() const
+const Models::Account * Models::Item::getParentAccount() const
 {
     const Item* p = this;
     
-    while (p != 0 && p->type != Item::account) {
+    while (p != nullptr && p->type != Item::account) {
         p = p->parentItemConst();
     }
     
-    return p;
+    return static_cast<const Account*>(p);
 }
 
 QString Models::Item::getAccountJid() const
 {
-    const Account* acc = static_cast<const Account*>(getParentAccount());
-    if (acc == 0) {
+    const Account* acc = getParentAccount();
+    if (acc == nullptr) {
         return "";
     }
     return acc->getLogin() + "@" + acc->getServer();
@@ -219,8 +234,8 @@ QString Models::Item::getAccountJid() const
 
 QString Models::Item::getAccountResource() const
 {
-    const Account* acc = static_cast<const Account*>(getParentAccount());
-    if (acc == 0) {
+    const Account* acc = getParentAccount();
+    if (acc == nullptr) {
         return "";
     }
     return acc->getResource();
@@ -228,8 +243,8 @@ QString Models::Item::getAccountResource() const
 
 QString Models::Item::getAccountName() const
 {
-    const Account* acc = static_cast<const Account*>(getParentAccount());
-    if (acc == 0) {
+    const Account* acc = getParentAccount();
+    if (acc == nullptr) {
         return "";
     }
     return acc->getName();
@@ -237,8 +252,8 @@ QString Models::Item::getAccountName() const
 
 Shared::Availability Models::Item::getAccountAvailability() const
 {
-    const Account* acc = static_cast<const Account*>(getParentAccount());
-    if (acc == 0) {
+    const Account* acc = getParentAccount();
+    if (acc == nullptr) {
         return Shared::Availability::offline;
     }
     return acc->getAvailability();
@@ -246,8 +261,8 @@ Shared::Availability Models::Item::getAccountAvailability() const
 
 Shared::ConnectionState Models::Item::getAccountConnectionState() const
 {
-    const Account* acc = static_cast<const Account*>(getParentAccount());
-    if (acc == 0) {
+    const Account* acc = getParentAccount();
+    if (acc == nullptr) {
         return Shared::ConnectionState::disconnected;
     }
     return acc->getState();
@@ -261,15 +276,24 @@ QString Models::Item::getDisplayedName() const
 void Models::Item::onChildChanged(Models::Item* item, int row, int col)
 {
     Item* parent = item->parentItem();
-    if (parent != 0 && parent == this) {
+    if (parent != nullptr && parent == this) {
         if (item->columnInvolvedInDisplay(col)) {
             int newRow = 0;
             std::deque<Item*>::const_iterator before = childItems.begin();
+            
+            Type ct = item->type;
+            if (ct == reference) {
+                ct = static_cast<Reference*>(item)->dereference()->type;
+            }
             while (before != childItems.end()) {
                 Item* bfr = *before;
-                if (bfr->type > item->type) {
+                Type bt = bfr->type;
+                if (bt == reference) {
+                    bt = static_cast<Reference*>(bfr)->dereference()->type;
+                }
+                if (bt > ct) {
                     break;
-                } else if (bfr->type == item->type && bfr->getDisplayedName() > item->getDisplayedName()) {
+                } else if (bt == ct && bfr->getDisplayedName() > item->getDisplayedName()) {
                     break;
                 }
                 newRow++;
@@ -293,3 +317,42 @@ bool Models::Item::columnInvolvedInDisplay(int col)
 {
     return col == 0;
 }
+
+void Models::Item::addReference(Models::Reference* ref)
+{
+    references.insert(ref);
+}
+
+void Models::Item::removeReference(Models::Reference* ref)
+{
+    std::set<Reference*>::const_iterator itr = references.find(ref);
+    if (itr != references.end()) {
+        references.erase(itr);
+    }
+}
+
+int Models::Item::getContact(const QString& jid) const
+{
+    int index = -1;
+    for (std::deque<Item*>::size_type i = 0; i < childItems.size(); ++i) {
+        const Models::Item* item = childItems[i];
+        const Contact* cnt = nullptr;
+        if (item->type == Item::reference) {
+            item = static_cast<const Reference*>(item)->dereferenceConst();
+        }
+        
+        if (item->type == Item::contact) {
+            cnt = static_cast<const Contact*>(item);
+            if (cnt->getJid() == jid) {
+                index = i;
+                break;
+            }
+        }
+    }
+    return index;
+}
+
+std::set<Models::Reference *>::size_type Models::Item::referencesCount() const
+{
+    return references.size();
+}
diff --git a/ui/models/item.h b/ui/models/item.h
index 77f2824..76f1780 100644
--- a/ui/models/item.h
+++ b/ui/models/item.h
@@ -24,11 +24,14 @@
 #include <QVariant>
 
 #include <deque>
+#include <set>
 
 #include "shared/enums.h"
 namespace Models {
 
 class Reference;
+class Contact;
+class Account;
     
 class Item : public QObject{
     friend class Reference;
@@ -82,11 +85,17 @@ class Item : public QObject{
         
         const Type type;
         
+        int getContact(const QString& jid) const;
+        std::set<Reference*>::size_type referencesCount() const;
+        
+        void addReference(Reference* ref);
+        void removeReference(Reference* ref);
+        
     protected:
         virtual void changed(int col);
         virtual void _removeChild(int index);
         virtual bool columnInvolvedInDisplay(int col);
-        const Item* getParentAccount() const;
+        virtual const Account* getParentAccount() const;
         
     protected slots:
         void onChildChanged(Models::Item* item, int row, int col);
@@ -95,7 +104,7 @@ class Item : public QObject{
         QString name;
         std::deque<Item*> childItems;
         Item* parent;
-        std::deque<Item*> references;
+        std::set<Reference*> references;
         
     protected slots:
         virtual void toOfflineState();
diff --git a/ui/models/reference.cpp b/ui/models/reference.cpp
index 4ead77f..26d6b94 100644
--- a/ui/models/reference.cpp
+++ b/ui/models/reference.cpp
@@ -17,39 +17,37 @@
  */
 
 #include "reference.h"
+#include <QDebug>
 
 using namespace Models;
 
 Models::Reference::Reference(Models::Item* original, Models::Item* parent):
     Models::Item(reference, {}, parent),
-    original(original)
+    original(original),
+    ax(-1),
+    bx(-1),
+    cx(-1),
+    c(false)
 {
-    original->references.push_back(this);
+    connect(original, &Item::childChanged, this, &Reference::onChildChanged);
+    connect(original, &Item::childIsAboutToBeInserted, this, &Reference::onChildIsAboutToBeInserted);
+    connect(original, &Item::childInserted, this, &Reference::onChildInserted);
+    connect(original, &Item::childIsAboutToBeRemoved, this, &Reference::onChildIsAboutToBeRemoved);
+    connect(original, &Item::childRemoved, this, &Reference::onChildRemoved);
+    connect(original, &Item::childIsAboutToBeMoved, this, &Reference::onChildIsAboutToBeMoved);
+    connect(original, &Item::childMoved, this, &Reference::onChildMoved);
     
-    connect(original, &Item::childChanged, this, &Item::childChanged);
-    connect(original, &Item::childIsAboutToBeInserted, this, &Item::childIsAboutToBeInserted);
-    connect(original, &Item::childInserted, this, &Item::childInserted);
-    connect(original, &Item::childIsAboutToBeRemoved, this, &Item::childIsAboutToBeRemoved);
-    connect(original, &Item::childRemoved, this, &Item::childRemoved);
-    connect(original, &Item::childIsAboutToBeMoved, this, &Item::childIsAboutToBeMoved);
-    connect(original, &Item::childMoved, this, &Item::childMoved);
+    original->addReference(this);
 }
 
 Models::Reference::~Reference()
 {
-    disconnect(original, &Item::childIsAboutToBeInserted, this, &Item::childIsAboutToBeInserted);
-    disconnect(original, &Item::childInserted, this, &Item::childInserted);
-    disconnect(original, &Item::childIsAboutToBeRemoved, this, &Item::childIsAboutToBeRemoved);
-    disconnect(original, &Item::childRemoved, this, &Item::childRemoved);
-    disconnect(original, &Item::childIsAboutToBeMoved, this, &Item::childIsAboutToBeMoved);
-    disconnect(original, &Item::childMoved, this, &Item::childMoved);
-    
-    for (std::deque<Item*>::const_iterator itr = original->references.begin(), end = original->references.end(); itr != end; itr++) {
-        if (*itr == this) {
-            original->references.erase(itr);
-            break;
-        }
-    }
+    disconnect(original, &Item::childIsAboutToBeInserted, this, &Reference::onChildIsAboutToBeInserted);
+    disconnect(original, &Item::childInserted, this, &Reference::onChildInserted);
+    disconnect(original, &Item::childIsAboutToBeRemoved, this, &Reference::onChildIsAboutToBeRemoved);
+    disconnect(original, &Item::childRemoved, this, &Reference::onChildRemoved);
+    disconnect(original, &Item::childIsAboutToBeMoved, this, &Reference::onChildIsAboutToBeMoved);
+    disconnect(original, &Item::childMoved, this, &Reference::onChildMoved);
 }
 
 int Models::Reference::columnCount() const
@@ -91,3 +89,79 @@ void Models::Reference::toOfflineState()
 {
     original->toOfflineState();
 }
+
+void Models::Reference::onChildChanged(Models::Item* item, int row, int col)
+{
+    if (item == original) {
+        emit childChanged(this, row, col);
+    }
+}
+
+void Models::Reference::onChildIsAboutToBeInserted(Models::Item* parent, int first, int last)
+{
+    if (parent == original) {
+        ax = first;
+        bx = last;
+    }
+}
+
+void Models::Reference::onChildInserted()
+{
+    if (ax != -1 && bx != -1) {
+        for (int i = ax; i <= bx; ++i) {
+            Reference* ref = new Reference(original->child(i));
+            Item::appendChild(ref);
+        }
+        ax = -1;
+        bx = -1;
+    }
+}
+
+void Models::Reference::onChildIsAboutToBeRemoved(Models::Item* parent, int first, int last)
+{
+    if (parent == original) {
+        for (int i = first; i <= last; ++i) {
+            Reference* ref = static_cast<Reference*>(childItems[i]);
+            Item* orig = original->child(i);
+            orig->removeReference(ref);
+            Item::removeChild(i);
+            delete ref;
+        }
+    }
+}
+
+void Models::Reference::onChildRemoved()
+{
+}
+
+void Models::Reference::onChildIsAboutToBeMoved(Models::Item* source, int first, int last, Models::Item* destination, int newIndex)
+{
+    if (destination == original) {
+        if (source != original) {
+            c = true;
+            ax = first;
+            bx = last;
+            cx = newIndex;
+            emit childIsAboutToBeMoved(source, first, last, destination, newIndex);
+        } else {
+            ax = newIndex;
+            bx = newIndex + last - first + 1;
+        }
+    }
+}
+
+void Models::Reference::onChildMoved()
+{
+    if (c) {
+        std::deque<Item*>::const_iterator beg = childItems.begin() + ax;
+        std::deque<Item*>::const_iterator end = childItems.begin() + bx + 1;
+        std::deque<Item*>::const_iterator tgt = childItems.begin() + cx;
+        std::deque<Item*> temp;
+        temp.insert(temp.end(), beg, end);
+        childItems.erase(beg, end);
+        childItems.insert(tgt, temp.begin(), temp.end());
+        emit childMoved();
+    } else {
+        onChildInserted();
+    }
+}
diff --git a/ui/models/reference.h b/ui/models/reference.h
index 84d0b07..8ec5352 100644
--- a/ui/models/reference.h
+++ b/ui/models/reference.h
@@ -30,7 +30,7 @@ class Reference : public Models::Item
 {
     Q_OBJECT
 public:
-    Reference(Models::Item* original, Models::Item* parent);
+    Reference(Models::Item* original, Models::Item* parent = 0);
     ~Reference();
     
     int columnCount() const override;
@@ -44,9 +44,21 @@ public:
 protected slots:
     void toOfflineState() override;
     
+private slots:
+    void onChildChanged(Models::Item* item, int row, int col);
+    void onChildIsAboutToBeInserted(Item* parent, int first, int last);
+    void onChildInserted();
+    void onChildIsAboutToBeRemoved(Item* parent, int first, int last);
+    void onChildRemoved();
+    void onChildIsAboutToBeMoved(Item* source, int first, int last, Item* destination, int newIndex);
+    void onChildMoved();
+    
 private:
     Models::Item* original;
-    
+    int ax;
+    int bx;
+    int cx;
+    bool c;
 };
 
 }
diff --git a/ui/models/roster.cpp b/ui/models/roster.cpp
index f1e6efa..91f1f74 100644
--- a/ui/models/roster.cpp
+++ b/ui/models/roster.cpp
@@ -62,6 +62,9 @@ QVariant Models::Roster::data (const QModelIndex& index, int role) const
     QVariant result;
     
     Item *item = static_cast<Item*>(index.internalPointer());
+    if (item->type == Item::reference) {
+        item = static_cast<Reference*>(item)->dereference();
+    }
     switch (role) {
         case Qt::DisplayRole:
         {
@@ -430,7 +433,8 @@ void Models::Roster::addContact(const QString& account, const QString& jid, cons
 {
     Item* parent;
     Account* acc;
-    Contact* sample = 0;
+    Contact* contact;
+    Reference* ref = 0;
     ElId id(account, jid);
     
     {
@@ -442,13 +446,18 @@ void Models::Roster::addContact(const QString& account, const QString& jid, cons
         acc = itr->second;
     }
     
-    for (std::multimap<ElId, Contact*>::iterator itr = contacts.lower_bound(id), eItr = contacts.upper_bound(id); itr != eItr; ++itr) {
-        sample = itr->second;                   //need to find if this contact is already added somewhere
-        break;                                  //so one iteration is enough
+    {
+        std::map<ElId, Contact*>::iterator itr = contacts.find(id);
+        if (itr == contacts.end()) {
+            contact = new Contact(acc, jid, data);
+            contacts.insert(std::make_pair(id, contact));
+        } else {
+            contact = itr->second;
+        }
     }
     
-    if (group == "") {       //this means this contact is already added somewhere and there is no sense to add it ungrouped
-        if (sample != 0) {
+    if (group == "") {
+        if (acc->getContact(jid) != -1) {
             qDebug() << "An attempt to add a contact" << jid << "to the ungrouped contact set of account" << account << "for the second time, skipping";
             return;
         } else {
@@ -464,41 +473,26 @@ void Models::Roster::addContact(const QString& account, const QString& jid, cons
         
         parent = itr->second;
         
-        for (int i = 0; i < parent->childCount(); ++i) {        //checking if the contact is already added to that group
-            Item* item = parent->child(i);
-            if (item->type == Item::contact) {
-                Contact* ca = static_cast<Contact*>(item);
-                if (ca->getJid() == jid) {
-                    qDebug() << "An attempt to add a contact" << jid << "to the group" << group << "for the second time, skipping";
-                    return;
-                }
-            }
+        if (parent->getContact(jid) != -1) {
+            qDebug() << "An attempt to add a contact" << jid << "to the group" << group << "for the second time, skipping";
+            return;
         }
         
-        for (int i = 0; i < acc->childCount(); ++i) {           //checking if that contact is among ugrouped
-            Item* item = acc->child(i);
-            if (item->type == Item::contact) {
-                Contact* ca = static_cast<Contact*>(item);
-                if (ca->getJid() == jid) {
-                    qDebug()    << "An attempt to add a already existing contact " << jid 
-                                << " to the group " << group 
-                                << ", contact will be moved from ungrouped contacts of " << account;
-                    
-                    parent->appendChild(ca);
-                    return;
-                }
-            }
+        int refIndex = acc->getContact(jid);
+        if (refIndex != -1) {           //checking if that contact is among ugrouped
+            qDebug()    << "An attempt to add a already existing contact " << jid 
+                        << " to the group " << group 
+                        << ", contact will be moved from ungrouped contacts of " << account;
+            ref = static_cast<Reference*>(acc->child(refIndex));
+            acc->removeChild(refIndex);
         }
         
     }
-    Contact* contact;
-    if (sample == 0) {
-        contact = new Contact(jid, data);
-    } else {
-        contact = sample->copy();
+    
+    if (ref == 0) {
+        ref = new Reference(contact);
     }
-    contacts.insert(std::make_pair(id, contact));
-    parent->appendChild(contact);
+    parent->appendChild(ref);
 }
 
 void Models::Roster::removeGroup(const QString& account, const QString& name)
@@ -515,33 +509,24 @@ void Models::Roster::removeGroup(const QString& account, const QString& name)
     
     parent->removeChild(row);
     
-    std::deque<Contact*> toInsert;
+    std::deque<Reference*> toInsert;
     for (int i = 0; item->childCount() > 0; ++i) {
-        Contact* cont = static_cast<Contact*>(item->child(0));
+        Reference* ref = static_cast<Reference*>(item->child(0));
         item->removeChild(0);
         
-        std::multimap<ElId, Contact*>::iterator cBeg = contacts.lower_bound({account, cont->getJid()});
-        std::multimap<ElId, Contact*>::iterator cEnd = contacts.upper_bound({account, cont->getJid()});
-        
-        int count = std::distance(cBeg, cEnd);
-        if (count > 1) {
-            for (; cBeg != cEnd; ++count, ++cBeg) {
-                if (cBeg->second == cont) {
-                    delete cont;
-                    contacts.erase(cBeg);
-                    break;
-                }
-            }
+        Contact* cont = static_cast<Contact*>(ref->dereference());
+        if (cont->referencesCount() == 1) {
+            toInsert.push_back(ref);
         } else {
-            toInsert.push_back(cont);
+            cont->removeReference(ref);
+            delete ref;
         }
     }
     
     if (toInsert.size() > 0) {
         Account* acc = accounts.find("account")->second;
         for (std::deque<Contact*>::size_type i = 0; i < toInsert.size(); ++i) {
-            Contact* cont = toInsert[i];
-            acc->appendChild(cont);             //TODO optimisation
+            acc->appendChild(toInsert[i]);             //TODO optimisation
         }
     }
     
@@ -552,19 +537,18 @@ void Models::Roster::removeGroup(const QString& account, const QString& name)
 void Models::Roster::changeContact(const QString& account, const QString& jid, const QMap<QString, QVariant>& data)
 {
     ElId id(account, jid);
-    std::multimap<ElId, Contact*>::iterator cBeg = contacts.lower_bound(id);
-    std::multimap<ElId, Contact*>::iterator cEnd = contacts.upper_bound(id);
+    std::map<ElId, Contact*>::iterator cItr = contacts.find(id);
     
-    for (; cBeg != cEnd; ++cBeg) {
+    if (cItr != contacts.end()) {
         for (QMap<QString, QVariant>::const_iterator itr = data.begin(), end = data.end(); itr != end; ++itr) {
-            cBeg->second->update(itr.key(), itr.value());
+            cItr->second->update(itr.key(), itr.value());
         }
-    }
-    
-    std::map<ElId, Room*>::iterator rItr = rooms.find(id);
-    if (rItr != rooms.end()) {
-        for (QMap<QString, QVariant>::const_iterator itr = data.begin(), end = data.end(); itr != end; ++itr) {
-            rItr->second->update(itr.key(), itr.value());
+    } else {
+        std::map<ElId, Room*>::iterator rItr = rooms.find(id);
+        if (rItr != rooms.end()) {
+            for (QMap<QString, QVariant>::const_iterator itr = data.begin(), end = data.end(); itr != end; ++itr) {
+                rItr->second->update(itr.key(), itr.value());
+            }
         }
     }
 }
@@ -572,18 +556,13 @@ void Models::Roster::changeContact(const QString& account, const QString& jid, c
 void Models::Roster::changeMessage(const QString& account, const QString& jid, const QString& id, const QMap<QString, QVariant>& data)
 {
     ElId elid(account, jid);
-    std::multimap<ElId, Contact*>::iterator cBeg = contacts.lower_bound(elid);
-    std::multimap<ElId, Contact*>::iterator cEnd = contacts.upper_bound(elid);
+    std::map<ElId, Contact*>::iterator cItr = contacts.find(elid);
     
-    for (; cBeg != cEnd; ++cBeg) {
-        for (QMap<QString, QVariant>::const_iterator itr = data.begin(), end = data.end(); itr != end; ++itr) {
-            cBeg->second->changeMessage(id, data);
-        }
-    }
-    
-    std::map<ElId, Room*>::iterator rItr = rooms.find(elid);
-    if (rItr != rooms.end()) {
-        for (QMap<QString, QVariant>::const_iterator itr = data.begin(), end = data.end(); itr != end; ++itr) {
+    if (cItr != contacts.end()) {
+        cItr->second->changeMessage(id, data);
+    } else {
+        std::map<ElId, Room*>::iterator rItr = rooms.find(elid);
+        if (rItr != rooms.end()) {
             rItr->second->changeMessage(id, data);
         }
     }
@@ -592,25 +571,26 @@ void Models::Roster::changeMessage(const QString& account, const QString& jid, c
 void Models::Roster::removeContact(const QString& account, const QString& jid)
 {
     ElId id(account, jid);
-    std::multimap<ElId, Contact*>::iterator cBeg = contacts.lower_bound(id);
-    std::multimap<ElId, Contact*>::iterator cEnd = contacts.upper_bound(id);
-    std::multimap<ElId, Contact*>::iterator cpBeg = cBeg;
+    std::map<ElId, Contact*>::iterator itr = contacts.find(id);
     
-    QSet<QString> toRemove;
-    for (; cBeg != cEnd; ++cBeg) {
-        Contact* contact = cBeg->second;
-        Item* parent = contact->parentItem();
-        if (parent->type == Item::group && parent->childCount() == 1) {
-            toRemove.insert(parent->getName());
+    if (itr != contacts.end()) {
+        Contact* contact = itr->second;
+        
+        contacts.erase(itr);
+        delete contact;
+        
+        std::set<ElId> toRemove;
+        for (std::pair<ElId, Group*> pair : groups) {
+            if (pair.second->childCount() == 0) {
+                toRemove.insert(pair.first);
+            }
         }
         
-        parent->removeChild(contact->row());
-        contact->deleteLater();
-    }
-    contacts.erase(cpBeg, cEnd);
-    
-    for (QSet<QString>::const_iterator itr = toRemove.begin(), end = toRemove.end(); itr != end; ++itr) {
-        removeGroup(account, *itr);
+        for (const ElId& elId : toRemove) {
+            removeGroup(elId.account, elId.name);
+        }
+    } else {
+        qDebug() << "An attempt to remove contact " << jid << " from account " << account <<" which doesn't exist there, skipping";
     }
 }
 
@@ -619,6 +599,12 @@ void Models::Roster::removeContact(const QString& account, const QString& jid, c
     ElId contactId(account, jid);
     ElId groupId(account, group);
     
+    std::map<ElId, Contact*>::iterator cItr = contacts.find(contactId);
+    if (cItr == contacts.end()) {
+        qDebug() << "An attempt to remove non existing contact " << jid << " from group " << group << " of account " << account <<", skipping";
+        return;
+    }
+    
     std::map<ElId, Group*>::iterator gItr = groups.find(groupId);
     if (gItr == groups.end()) {
         qDebug() << "An attempt to remove contact " << jid << " from non existing group " << group << " of account " << account <<", skipping";
@@ -626,57 +612,26 @@ void Models::Roster::removeContact(const QString& account, const QString& jid, c
     }
     Account* acc = accounts.find(account)->second;  //I assume the account is found, otherwise there will be no groups with that ElId;
     Group* gr = gItr->second;
-    Contact* cont = 0;
+    Contact* cont = cItr->second;
     
-    unsigned int entries(0);
-    unsigned int ungroupped(0);
-    for (std::multimap<ElId, Contact*>::iterator cBeg = contacts.lower_bound(contactId), cEnd = contacts.upper_bound(contactId); cBeg != cEnd; ++cBeg) {
-        ++entries;
-        Contact* elem = cBeg->second;
-        if (elem->parentItem() == acc) {
-            ++ungroupped;
-        }
+    int contRow = gr->getContact(jid);
+    if (contRow == -1) {
+        qDebug() << "An attempt to remove contact " << jid << " of account " << account << " from group " << group  <<", but there is no such contact in that group, skipping";
+        return;
+    }
+    Reference* ref = static_cast<Reference*>(gr->child(contRow));
+    gr->removeChild(contRow);
+    
+    if (cont->referencesCount() == 1) {
+        qDebug() << "An attempt to remove last instance of contact" << jid << "from the group" << group << ", contact will be moved to ungrouped contacts of" << account;
+        acc->appendChild(ref);
+    } else {
+        cont->removeReference(ref);
+        delete ref;
     }
     
-    if (ungroupped == 0 && entries == 1) {
-        for (std::multimap<ElId, Contact*>::iterator cBeg = contacts.lower_bound(contactId), cEnd = contacts.upper_bound(contactId); cBeg != cEnd; ++cBeg) {
-            if (cBeg->second->parentItem() == gr) {
-                cont = cBeg->second;
-                break;
-            }
-        }
-        
-        if (cont == 0) {
-            qDebug() << "An attempt to remove contact " << jid << " of account " << account << " from group " << group  <<", but there is no such contact in that group, skipping";
-            return;
-        }
-        
-        qDebug() << "An attempt to remove last instance of contact" << jid << "from the group" << group << ", contact will be moved to ungrouped contacts of" << account;
-        acc->appendChild(cont);
-        
-        if (gr->childCount() == 0) {
-            removeGroup(account, group);
-        }
-    } else {
-        for (std::multimap<ElId, Contact*>::iterator cBeg = contacts.lower_bound(contactId), cEnd = contacts.upper_bound(contactId); cBeg != cEnd; ++cBeg) {
-            if (cBeg->second->parentItem() == gr) {
-                cont = cBeg->second;
-                contacts.erase(cBeg);
-                break;
-            }
-        }
-        
-        if (cont == 0) {
-            qDebug() << "An attempt to remove contact" << jid << "of account" << account << "from group" << group  <<", but there is no such contact in that group, skipping";
-            return;
-        }
-        
-        gr->removeChild(cont->row());
-        cont->deleteLater();
-        
-        if (gr->childCount() == 0) {
-            removeGroup(account, group);
-        }
+    if (gr->childCount() == 0) {
+        removeGroup(account, group);
     }
 }
 
@@ -738,50 +693,46 @@ void Models::Roster::onChildRemoved()
 void Models::Roster::addPresence(const QString& account, const QString& jid, const QString& name, const QMap<QString, QVariant>& data)
 {
     ElId contactId(account, jid);
-    std::multimap<ElId, Contact*>::iterator cBeg = contacts.lower_bound(contactId);
-    std::multimap<ElId, Contact*>::iterator cEnd = contacts.upper_bound(contactId);
-    for (;cBeg != cEnd; ++cBeg) {
-        cBeg->second->addPresence(name, data);
+    std::map<ElId, Contact*>::iterator itr = contacts.find(contactId);
+    if (itr != contacts.end()) {
+        itr->second->addPresence(name, data);
     }
 }
 
 void Models::Roster::removePresence(const QString& account, const QString& jid, const QString& name)
 {
     ElId contactId(account, jid);
-    std::multimap<ElId, Contact*>::iterator cBeg = contacts.lower_bound(contactId);
-    std::multimap<ElId, Contact*>::iterator cEnd = contacts.upper_bound(contactId);
-    for (;cBeg != cEnd; ++cBeg) {
-        cBeg->second->removePresence(name);
+    std::map<ElId, Contact*>::iterator itr = contacts.find(contactId);
+    if (itr != contacts.end()) {
+        itr->second->removePresence(name);
     }
 }
 
 void Models::Roster::addMessage(const QString& account, const Shared::Message& data)
 {
     ElId id(account, data.getPenPalJid());
-    
-    std::multimap<ElId, Contact*>::iterator cBeg = contacts.lower_bound(id);
-    std::multimap<ElId, Contact*>::iterator cEnd = contacts.upper_bound(id);
-    
-    for (;cBeg != cEnd; ++cBeg) {
-        cBeg->second->addMessage(data);
-    }
-    
-    std::map<ElId, Room*>::const_iterator rItr = rooms.find(id);
-    if (rItr != rooms.end()) {
-        rItr->second->addMessage(data);
+    std::map<ElId, Contact*>::iterator itr = contacts.find(id);
+    if (itr != contacts.end()) {
+        itr->second->addMessage(data);
+    } else {
+        std::map<ElId, Room*>::const_iterator rItr = rooms.find(id);
+        if (rItr != rooms.end()) {
+            rItr->second->addMessage(data);
+        }
     }
 }
 
 void Models::Roster::dropMessages(const QString& account, const QString& jid)
 {
     ElId id(account, jid);
-    for (std::multimap<ElId, Contact*>::iterator cBeg = contacts.lower_bound(id), cEnd = contacts.upper_bound(id) ;cBeg != cEnd; ++cBeg) {
-        cBeg->second->dropMessages();
-    }
-    
-    std::map<ElId, Room*>::const_iterator rItr = rooms.find(id);
-    if (rItr != rooms.end()) {
-        rItr->second->dropMessages();
+    std::map<ElId, Contact*>::iterator itr = contacts.find(id);
+    if (itr != contacts.end()) {
+        itr->second->dropMessages();
+    } else {
+        std::map<ElId, Room*>::const_iterator rItr = rooms.find(id);
+        if (rItr != rooms.end()) {
+            rItr->second->dropMessages();
+        }
     }
 }
 
@@ -799,10 +750,10 @@ void Models::Roster::removeAccount(const QString& account)
     accountsModel->removeAccount(index);
     accounts.erase(itr);
     
-    std::multimap<ElId, Contact*>::const_iterator cItr = contacts.begin();
+    std::map<ElId, Contact*>::const_iterator cItr = contacts.begin();
     while (cItr != contacts.end()) {
         if (cItr->first.account == account) {
-            std::multimap<ElId, Contact*>::const_iterator lItr = cItr;
+            std::map<ElId, Contact*>::const_iterator lItr = cItr;
             ++cItr;
             contacts.erase(lItr);
         } else {
@@ -838,7 +789,7 @@ void Models::Roster::removeAccount(const QString& account)
 QString Models::Roster::getContactName(const QString& account, const QString& jid)
 {
     ElId id(account, jid);
-    std::multimap<ElId, Contact*>::const_iterator cItr = contacts.find(id);
+    std::map<ElId, Contact*>::const_iterator cItr = contacts.find(id);
     QString name = "";
     if (cItr == contacts.end()) {
         std::map<ElId, Room*>::const_iterator rItr = rooms.find(id);
@@ -971,15 +922,14 @@ bool Models::Roster::groupHasContact(const QString& account, const QString& grou
     if (gItr == groups.end()) {
         return false;
     } else {
-        const Group* gr = gItr->second;
-        return gr->hasContact(contact);
+        return gItr->second->getContact(contact) != -1;
     }
 }
 
 QString Models::Roster::getContactIconPath(const QString& account, const QString& jid, const QString& resource)
 {
     ElId id(account, jid);
-    std::multimap<ElId, Contact*>::const_iterator cItr = contacts.find(id);
+    std::map<ElId, Contact*>::const_iterator cItr = contacts.find(id);
     QString path = "";
     if (cItr == contacts.end()) {
         std::map<ElId, Room*>::const_iterator rItr = rooms.find(id);
diff --git a/ui/models/roster.h b/ui/models/roster.h
index 34c343c..d866b6d 100644
--- a/ui/models/roster.h
+++ b/ui/models/roster.h
@@ -32,6 +32,7 @@
 #include "contact.h"
 #include "group.h"
 #include "room.h"
+#include "reference.h"
 
 namespace Models
 {
@@ -87,7 +88,7 @@ private:
     Item* root;
     std::map<QString, Account*> accounts;
     std::map<ElId, Group*> groups;
-    std::multimap<ElId, Contact*> contacts;
+    std::map<ElId, Contact*> contacts;
     std::map<ElId, Room*> rooms;
     
 private slots:
diff --git a/ui/squawk.cpp b/ui/squawk.cpp
index 26d69e0..41634ad 100644
--- a/ui/squawk.cpp
+++ b/ui/squawk.cpp
@@ -305,6 +305,9 @@ void Squawk::onRosterItemDoubleClicked(const QModelIndex& item)
 {
     if (item.isValid()) {
         Models::Item* node = static_cast<Models::Item*>(item.internalPointer());
+        if (node->type == Models::Item::reference) {
+            node = static_cast<Models::Reference*>(node)->dereference();
+        }
         Models::Contact* contact = 0;
         Models::Room* room = 0;
         QString res;
@@ -681,7 +684,9 @@ void Squawk::onRosterContextMenu(const QPoint& point)
     QModelIndex index = m_ui->roster->indexAt(point);
     if (index.isValid()) {
         Models::Item* item = static_cast<Models::Item*>(index.internalPointer());
-    
+        if (item->type == Models::Item::reference) {
+            item = static_cast<Models::Reference*>(item)->dereference();
+        }
         contextMenu->clear();
         bool hasMenu = false;
         bool active = item->getAccountConnectionState() == Shared::ConnectionState::connected;
@@ -1105,6 +1110,9 @@ void Squawk::onRosterSelectionChanged(const QModelIndex& current, const QModelIn
     
     if (current.isValid()) {
         Models::Item* node = static_cast<Models::Item*>(current.internalPointer());
+        if (node->type == Models::Item::reference) {
+            node = static_cast<Models::Reference*>(node)->dereference();
+        }
         Models::Contact* contact = 0;
         Models::Room* room = 0;
         QString res;