Creating A PvP Scenario and Setting Forces

[Grymmli]

I've been working on a scenario that acts as a sort of conquest map where players fight for control over indestructible infinity chests as the only resources on the map, so ive got the entire map done and the two starting fortresses are set up but i cant for the life of me figure out how to assign players to forces other than 'player', is there a mod that can have players choose their force when loading the map? because at this point i cant even get the lua command to work.