global TestAttunementForSomeInstance = function(plr)
{
    // check for a quest
    if(plr.HasFinishedQuest(7487) == 1 && plr.IsGroupLeader())
        {
            return 1;
        }
    plr.BroadcastMessage("You do not have the required attunement to enter this instance. j00 suck!");
    return 0;
}

// register in script system
.RegisterAreaTriggerEvent(2886, TestAttunementForSomeInstance);