One of my cats was recently put to sleep due to health problems. About a week later, we got stuck with another cat- turns out my cousin was abusing her, so we took her.

Her and my other two cats don't get along. We've managed to get her to trust us- she's actually very lovable, if skittish- but she freaks the fuck out whenever one of the other girls is in the same room as her, and they do the same.

Is there anything I can do to facilitate them being less hostile? She tolerated the other cat my cousin had.

Pic related, my boy who was put down. =[