There are four of us. Recently, we were on a school trip with another class in the theater. There is a boy in this other class, who is a one of us's boyfriend. Let's call that girl Kate. There is a one friend, let's call her Agatha who was mad at Kate because at the last minute she told her that she was sitting on the bus with her boyfriend not with Agatha. During the trip she was also with him all the time, she didn't even come to our group to even talk. Agatha is the type of quickly irritating person and quickly offends. She is pissed off at Kate because the boy, according to agatha, was more important to her than us. For me and the fourth of us, let's call her Emily, we didn't mind Kate's behavior, but now there is war between Kate and agatha and I don't know what to do. Any advice on how to solve this?