I have a total of six cats, four of whom were intentional adoptions from a shelter, the other two were "we were found by the cat" adoptions. The five cats who were already in residence: Circe - approx age 10.5 years, she's been mine for 4 years Autumn - approx age 6.5 years, also mine for 4 years Domino - approx age 6 years, only male (neutered), mine for 4.5 years TV - approx age 6 years, mine for 4.5 years Cosette - approx age 3.5 years, mine for 2.5 years Newcomer: Mabel, now probably about 6 months (based on teeth at her first vet visit, probably born during April of this year), she's been with us since August and was spayed mid-September Mabel is really bonded with my youngest son, whose bedroom is upstairs (with a separate bathroom up there), and when she first came here, she was alone up there until we got her clean bill of health. The issue with trying to integrate Mabel with the other cats is Mabel herself. She hisses at the other cats, while the other cats just kind of look at her with what seems like a mildly amused expression, there is no poofing of tails or arching of backs from the older 5 cats--only from Mabel. There hasn't been anything physical unless Mabel swipes at one of them (mostly Cosette or TV), and they will turn around hiss and whap her one (but still no poofing/arching back and Mabel is the only one whose ears go flat). So I don't know how to get Mabel integrated with the others. The other five have no objections to her presence (they will walk right past her into the kitchen and eat while she's posturing). We've tried brushing back and forth for scent transfer. Currently, Mabel eats separately from the others. So is Mabel just a cat who should be solitary, or is there hope for her to get along with the others?