maybe let ships travel even though enemy territory if you don NOT have a fight treaty with that clan you want to travel through and won't attack that faction where you are travel through.
So if you want to attack V and are UnalignedWorlds, you can't travel through V planets, can't travel though Ascended planets, but through FreeMachines or TrueBorn, because they support that you attack Ascended.
^^ Or make that only possible against the biggest 2 factions.
I think there should be 2 biggest factions and not only 1, since if some faction is only a bit bigger, both can overrun all others to get planets for fighting the other clan.