Multiple forces... on a team... What do you mean exactly? Do you mean player groups? Player arrays? Please be more accurate in your... description...
If you mean having multiple players on the same team, this is set in player properties, but if you mean having player forces you set on player properties setting be on the same team... The thing is to set every player of the forces into a player group and putting alliances between difference forces...
But I don't think I understand...