I have the same situation sometimes. Usually we just make it so it is everyone against everyone and if one person is doing too well in the game there is nothing that says the other two can't suddenly join forces for awhile to hurt you so you're not winning any more. I like it because it is challenging (sp?) and you never know who will join forces (temporary alliances) and then to see someone backstab the person they had just joined forces not more than two hands ago.
Aquain.
"Without me the earth wouldn't turn the sun wouldn't shine and the stars at night wouldn't twinkle" -Aquain