I have three Siamese-mixed cats roughly two years old and from the same litter. I acquired from a family a sister (Nala) and brother (Simba) pair about 1 1/2 years ago when they were roughly 7 months old. Then we acquired the other brother (Sammie) just recently. We didn't get all three at the same time because Sammie was already adopted out to a family who unfortunately discovered they were allergic to him so they had to return him back to the same people we got all 3 from. He was with them for about a year then the 'mom' had to have surgery on her back and so she decided that she had quite a few animals and she hinted to me that she wanted to give him up due to her back. After seeing his pictures I fell in love with him and so my husband and I went over to see him in person. We brought him to our house on a 'trial' letting the other family know that we might return him if it didn't work out. .
My situation is now Simba will bully Sammie any time Sammie is active. He won't let him go near the food dishes or play by the toys without a hiss, growl or swipe of intimidation. We have tried separation by putting Simba and Nala in separate rooms from Sammie overnight, putting their food on the floor on opposite sides of the door and tried to encourage positive play. Simba won't bully Sammie when Sammie sits on the couch or when my husband or I am present but he'll bully all other shared spaces of the area that they are in and when we aren't watching and when he thinks we aren't paying attention. The female Nala used to hiss at Sammie but she has learned to back off and will now let him roam.
My husband and I haven't seen any loss of fur or bloodshed but we don't want to get to that point. I am doing my best to not relocate Sammie back to the previous mommy who had the surgery.
I would appreciate any advice.
We are considering using Feliway then if that doesn't work Spirit Essence: Bully Remedy and Safe Space. Has anyone heard of or had any experience with those?