One of my pals told us that you fight multiple enemies differently depending on whether you draw them all together or you draw an ememy while there is already one on the space.
According to him they fight one by one in the first case whilst they fight together in the second case. I can't find a line about it in the manual but perhaps it's in a FAQ I don't know?
Perhaps someone can clarify this for us as we've used this rule for years.without really thinking about it.