Yeah, that was just Supernova as far as I know. Though there have been instances where a member simply stays out of it, from either side. Thats why I discourage being in two factions being actively hostile to each other, though I allow it.
For a good example of how they can do multiple factions, several AW have been in Phantoms, including myself. Alpha still is. Phantoms and AW have been enemies of each other (bitter enemies in RP) nearly since the Phantoms were created. Yet the AW members in Phantoms do it in a good way. If something is shaping up between AW and Phantoms, they stay with whatever side they came into the server on. Or if in neither, they would usually switch to the outnumbered side, evening forces more. (Those even fights were really nice actually..)
It all depends on how the player acts with the fact of being in two factions.