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...
The World Editor term "force" is what defines the team or any variation of group of players. If you want them on the same team, go to force properties and put them all in the same force, and check the box that says "allied" and any other of those boxes you so desire.
he means how to u turn one player against each other as to have his own unit fight against him ive seen it happen before as in loap the grave keeper job the ghost a neutral but are unallied to u but other neutral units are not.
Stop flaming, now. If that's what he meant, then he must create a trigger which gives some of his units to neutral hostile (or a CPU-controlled AI player) without changing colors.