Using TC structure allowing easier patches importing

src/server/game/Groups/GroupReference.cpp

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2016+     AzerothCore <www.azerothcore.org>, released under GNU GPL v2 license: http://github.com/azerothcore/azerothcore-wotlk/LICENSE-GPL2
+ * Copyright (C) 2008-2016 TrinityCore <http://www.trinitycore.org/>
+ * Copyright (C) 2005-2009 MaNGOS <http://getmangos.com/>
+ */
+
+#include "Group.h"
+#include "GroupReference.h"
+
+void GroupReference::targetObjectBuildLink()
+{
+    // called from link()
+    getTarget()->LinkMember(this);
+}
+
+void GroupReference::targetObjectDestroyLink()
+{
+    // called from unlink()
+}
+
+void GroupReference::sourceObjectDestroyLink()
+{
+    // called from invalidate()
+}
+