Say I have a mission that involves the player and players group, some mercenaries, some police, some east soldiers, civilians, and the "rogue group".
I want the mercenaries to target the players and police.
I want the police to target the mercenaries and any other "east" units they encounter as well as the rogues.
The east soldiers will target the players group, the police, and the rogue group.
the civilians will get in the way.
The rogue group will shoot anything that moves.
Hope that makes sense. For the most part the mercs and rogues are the ones I think may give me trouble.