That's understandable that you don't want to see your friends in such condition but you said that they do this only when they are in big groups. The solution is to meet only few of them at a time.
I think he's handsome but not THAT handsome. Girls wouln'd be so crazy about Robert if he doesn't impersonate Edward. Is there anybody who remember him as Cedric from Harry Potter? Quite so.
I think you two should talk about it before it's too late. You may loose a friend... or maybe she just needs a little care and is not truly interested. idk