Edit: I probably need to read your post better. What exactly do you mean? If you mean -leader- (i.e., squad leader) then it's just a matter of reorganizing who's joining who (units group1 Join grpMember2), but if you're wondering about the new ArmA command
formationLeader then the below is pertinent. Note however they won't be permanent formationleaders since they generally won't have an AI of their own, but you -can- use it to activate other scripts and such. In my RUG DSAI I use the formationLeader command to activate one kind of voice.
2,3,4 go to THAT BUSH at 6 o'clock!
-> Makes 2 the FormationLeader of 2, 3 & 4.
4, Attack that TANK at 12 o'clock!
-> Makes 4 his own formation leader. Also works for AI-engage.
Etc etc. Basically any action in which the squad leader orders the units to break off from the formation will cause the formationLeader to change.
Including getting into a vehicle, using the "Take cover" option and many more. Flanking, advancing and staying back does not AFAIK change formationleader.
How so?
Wolfrug out.