Jagged Alliance is a military strategy game series that originated on PC in 1994, involving player-controlled squads of mercenaries. Not only do the mercs have different skills, they interact differently with one another when teamed up. The player's actions lend a reputation that also affects the mercenaries' willingness to work.
[Update: Eric pointed out that Strategy First officially cancelled all their projects. Either Empire has picked up the pieces or this is an unrelated project.]