Is it related to influence at all? I've heard things about other CSs and civs going to war or changing their diplomatic status with you depending on how you treat other civs or CSs. Is this true? If so how does it work? Is it safe to go around smashing CSs without all the other civs and CSs getting mad at you? I would like to know how this works before starting wars.
Edit: How does this effect teams? My sister and I are playing LAN and we're on the same team. If she attacks some city states, what happens to me? What happens if she starts and I help? Also, when a CS says "We have a serious dispute with X, please murder them for us," does that work the other way around? If I kill Y and help X instead, do I get anything for it?