InstanceData: Add function to check wether server allows two side groups

--HG--
branch : trunk

src/game/InstanceData.h

@@ -22,6 +22,7 @@
 #define TRINITY_INSTANCE_DATA_H
 
 #include "ZoneScript.h"
+#include "World.h"
 //#include "GameObject.h"
 //#include "Map.h"
 
@@ -164,6 +165,9 @@ class InstanceData : public ZoneScript
         // Remove Auras due to Spell on all players in instance
         void DoRemoveAurasDueToSpellOnPlayers(uint32 spell);
 
+        // Return wether server allow two side groups or not
+        bool ServerAllowsTwoSideGroups() { return sWorld.getConfig(CONFIG_ALLOW_TWO_SIDE_INTERACTION_GROUP); }
+
         virtual bool SetBossState(uint32 id, EncounterState state);
         EncounterState GetBossState(uint32 id) const { return id < bosses.size() ? bosses[id].state : TO_BE_DECIDED; }
         const BossBoundaryMap * GetBossBoundary(uint32 id) const { return id < bosses.size() ? &bosses[id].boundary : NULL; }