I have adopted senior cats several times. They are really, really slow to acclimate. I had one cat then spent up to 80 percent of her time in my bedroom, closed off to the other cats. It took about a year for her to get where she would tolerate them being around and they would tolerate her. Even then, sometimes scuffles would break out. I would give her another break by putting her back in the bedroom and allowing her to take some time away from the others. Thanks for adopting a senior cat. It can take time---a long time. But getting love and acceptance from you and realizing that she is safe will help. Cats have to hiss and chase as they figure out the new pecking order. It takes a lot of patience.