(((((((((((((( katebabe ))))))))))))))))))

Have you tried to talk to alex one on one and tell her your concerns about her behavior?
When I was your age I don't know what I would have done in this situation, as an adult however I suggest that you try to talk to her and if that don't work then I think you should bring it to the attention of a trusted adult, maybe they can talk to her. I am sorry if I am not being helpful.