open the unit in object editor and give it insanly high sight and aqqusiton range OR give that player (zombies should NOT be creeps or they will only go so far (under advancent options gameplay maxium creep range)) vision of the whole map and a trigger to pick all units owned by player "zombies rule the wrold muahahahhahaha" and order them to attck all units owned by the humanes
this is somwwaht unrealstic i mean zombies have rotten eyesight (pun inteeded) so how acn they see whole map? i say give them random attck moves to a random point in playable map area that'll be cool a game where the enemys dont have to know where you are! aand you can make doodads with occeldar heights above 0 so they can block sight and you can hide behind them. coolest thing ever but im rambleing atnd its your map if you dont use it (and even if you do) ill probely use it.