If your middle-schooler had a friend who was bullying another of her friends....?

I wouldn't take it to the parents because I'm sure there's something about the way they raise their children to be or not be respectful to others. At this point since talking to her friend isn't working, I would probably suggest that she does the same to the girl who is bullying just to prove to her that nobody likes to be disrespected and annoyed and see how that goes.....