cat behavior problem

[tansea]

I am owned by 5 kitties and 1 parrot. They are the loves of my life.
there is a problem with the cats, 1 is calico and 3 are tabbys the last is grey and white. My problem is the 4 gang up on the calico. She also goes after them at times.
My question is ... are cats prejudiced against Calico's? The reason I*'m asking is I had a sweet Calico who passed last year, Ginger was with this same group of cats and they treated her the same. She 21 years old when she passed. She used to fight back but as he got older she mostly just hid.
I would also like to know if anyone has any suggestions how to change this behavior.
Thank you so much in advance for any ideas you can give me