OpenRA

Is there a way I can specify certain units on a skirmish map to not move and only return fire? If I assign them to a team and the AI fills that slot, often they simply charge them at the start of the game.

Failing that, is there a way I can specify all the enemy units not to move and simply return fire?

The "AutoTarget" trait has the field "InitialStanceAI" which is set to "AttackAnything" by default. Should be as simple as changing that to "ReturnFire".