Help in dealing with a violent, mentally ill resident?

I feel almost at my wits end. We recently acquired a new resident (Resident C) who was deemed unsafe to be at home due to mental illness. Originally she was roomed with Resident A, but Resident A kept throwing all hung up clothes of Resident C's onto her (Resident A's) bed and sleeping on them, a common behavior of Resident A with any blanekt, clothes, ect. Resident C was also very possessive of Resident A and believed we were drugging her due to Resident A being a fan of cat naps. Resident A changed rooms with Resident B so that Resident B now roomed with Resident C. Resident C was originally violently kicking out Resident B and trying to drag Resident A back into her room, but over the past few days has become super possessive of Resident B, calling her her wife, which we correct in an effort to discourage this behavior.

Resident B is very prone to violent behaviors. She's attacked staff member in fits of rage ranging for trying to get out to trying to steal our cellphones from our pockets (she is coming from a home setting and knows everyone pretty much has a cellphone.) I myself lock my phone in the office for this reason. She has strangled me twice now and another caregiver once due to not getting her way. She also has no concept of personal space and gets very touchy feely and tries to kiss both staff members and other residents.

Today she kept roughly grabbing and trying to bring Resident B with her to their room, and such. We stepped between them multiple times and as the most experienced caregiver, I made the call for Resident B to sleep in the lobby in a recliner for her own safety. I have stepped between Resident C and Resident B quite a few times to provide a shield for Resident B.

Resident B is being abused by Resident C in my and several other's opinions, but higher ups won't listen. What are our options and does anyone have any advice or tips for dealing with these behaviors? Today was bad enough that for all residents safety we had the woman stay in her room and she interrupted/delayed care for everyone else because we had to act like prison wardens.

I speak in a firm, clear tone with Resident C, using simple terms she can understand. I stand my ground (defensively) and stay consistent in what is and isn't allowed. I do not raise my voice and do not take on an aggressive stance.

I do not want to be a prison warden I want to be a caregiver and be able to give all the residents the best care possible. We are designating panic areas due to this Resident's behaviors, which we are heavily documenting.