So recently we took in an older family pet, he couldn't live with my parents any longer so 5yo Spartapuss came to live with me and my fiance in our flat. He was essentially my cat for 3 years and when i moved out we decided not to upset the balance he had with our other family cat so left him behind. He moved on Saturday and he seems to be adjusting well so far.
Only issue is that we have two 1yo cats, a boy Drogo and a girl Khaleesi. Both are outdoor cats and we fitted a cat flap so they come and go as they please.
Neither has taken well to Spartapuss invading their territory, understandable, so we set up a safe area for them in the spare room where they spend most of their time and Spartapuss has his area in our bedroom for now. We've let them get small glimpses of eachother (apart from Drogo and Spartapuss' first meeting which happened unexpectedly, lots of sniffing and curiosity before the defence mechanisms kicked in). We open and close the safe spaces to allow time for each to roam the flat and get used to the scent of the others regularly. Rotating every few hours provided the kittens arent outside.
Drogo has no real issue with Spartapuss, they can be in the same room and bar from some small confrontation, they generally leave eachother alone or just avoid eachother. However our girl Khaleesi, every time Spartapuss see's her, he moves towards her and she runs a mile. It's unusual behaviour from him, especially given how passive he is towards Drogo and having lived in a multi cat household before.
We want to let him out to roam as he is an outdoor cat but we're terrified he'll scare away Khaleesi so she won't come back or otherwise hurt her. there's only one door (our own private front door that leads directly outside) so they are guaranteed to meet and we're worried if he scares her away from the house entrance she wont want to come back.
Any advice would be welcome.