Lease

I have a tenant that constantly does not get along with her 2 other room mates. In the last 8 months I have been through 6 different room mates for that 0ne apartment because of her. She remained. This is during a 1 year lease term. Every roommate wants to break their lease because they don't get along with her. She acts like she owns the apartment, her way or the highway, like an army general. She smokes weed all day long... Now one more roommate wants to leave because of her. When ever a person leaves or wants to break their lease they have to find a replacement roommates to take over there portion of their lease but now I am just fed up with her. I want her out. What I want to no is this: If the original 3 roommates signed a lease together and the lease is broken because of the conflict but the roommates that broke the lease find replacement roommates who hasn't signed a lease yet, is the original lease still valid for the troublemaker roommate?