I played the mission Friends of Old (CG pg. 11) as the Imperial player. There are special rules that state, "A hero can interact with a mission token (Insight) to reveal that token and replace it with a Rebel Trooper figure. Heroes control Rebel Troopers as allies."

There are 4 mission tokens. During the mission, there were 2 Rebel Troopers on the board when the Rebel players asked, does each Rebel Trooper have its own activation, or are they considered a group and all act at once?

I left the decision up to them, and they chose to activate them all at once as a group. I don't think there is a rule concerning this situation, is there?

I believe that due to the fact that the Rebel Troops are one "card" that they activate at the same time, much like a group of Stormtroopers. Err...unless you end up with Four on the table, and then that would be two cards, as a single card only houses three troops. If that's what you're asking, I mean.