Boy, I wish I knew the answer, Sandie. My Peeka bullied my sweet Pidge every day. Poor Pidge lived under my bed for a long time, coming out only to eat and use the litter box. It wasn't until I brought home my CH baby Creamsicle that, for some reason, Peeka stopped bullying Pidge. It's as though Cgirl had a calming effect on the household. I wish I could come up w/constructive ideas but, like you, I tried everything I could think of, even once holding Pidge in my arms and holding her paw to smack Peeka back. Poor Pidge cringed and looked at me as though I'd lost my mind and it didn't work anyhow. Peeka wasn't impressed. Good luck w/this. I know how tough it can be but it's even worse for sweet Mandy.