I have 2 cats and sometimes they clean each other. When they do, they face each other and cat 1 cleans cat 2’s back area near the tail, and cat 2 cleans near cat 1’s shoulder blades. In the past 6 months, cat 1 has started losing hair between his shoulder blades because cat 2 is chewing his fur while they are cleaning each other. Is there anything I can do to keep her from doing this other than making loud sounds to scare her away from him?