There are people that don't do this anyway?
Anyway have a rule.
Chain of command: all squads must follow basic military structure, plenty of Pvts, a handful of NCOs and 1-2 officers or 2-3 officers and a bunch of NCOs, works best if you mod the transports to be bigger.
It gets stupidly hard once you'd normally be fielding full squads of captains and the like.