How about this idea. Two teams. One alien one human. Each side has two squads that compete for win. This could be usefull for some type of tournament.
Then make a script that divides humans evenly between the two human squads. THe same would go for aliens.
But this would require a new gametype

and maybe even squad models with just a differant color. Like white and black. or red and blue. You cannot attack somone on your same team (race) but only the other race (team)