Well the AI seems to ask people about once every five turns to join them in a war. So if it's not doable it's likely that the human player(if nothing else) will get dragged into the war anyway. Regardless I'd really like to see some of the bad blood civs duke it out. EDIT: Here's an idea, not sure if it could be done modularly though. What if, when a war breaks out, any uninvolved civs with a +5/-5 relations with one of the involved civs gets too protect/attack that civ? Maybe force their involvement if they have +10/-10. I think things are more realistic that way. If you attack a little civ that someone really really likes they come after you. And if someone you absolutely hate goes to war, you hop in on the other side because you were just waiting for a reason.