Do you generally keep your groups together (for example, stormies), or split them up? Thought being as a group they can inflict max damage in one activation, but risk being taken out as a group, but split up, if the focus from the opponent is in one area, you can avoid losing the whole group. So, if you have two different stormtrooper groups, would you mix and match them if you were heading in different directions?

I guess it sort of depends on the scenario, but often I'll put them in pairs, and then send the 3rd to hang out with a different group. helps with reinforcing them later.

Depends on the scenario, the opponent's list, the opponent's tactic ... sometimes, I even switch in the middle of the game ...

I usually keep them together. The focus fire from 3 troopers is very dangerous. If the group suffers some casualties, then it's easy enough for the last troopers to run away. There aren't many things that can drop 3 troopers in one go.

That being said... that's for elite troopers. The regular ones are quite squishy so for them it's usually better to split them up.

In general though, it's a choice between easier surviability or more damage output.