Summerdale was allied with astrum so I don't think that really valid.
It was an empty alliance. A previous ruler signed it without consulting the realm at all, because the two rulers were friends.
Besides, it is still a war that a pair of SA realms fought, where the entire SA hegemony didn't dog-pile onto the other side. That fits the criteria asked for. Don't be putting on all kinds of extra, after-the-fact conditions to narrow out any inconvenient examples.
