Last November my mother and her 3 cats moved in with my sister and her 2 cats. We set up a separate feeding station and cat box in my mother's room and kept the door closed until her kitties got used to the new house. My sister's 2 cats were very interested in the new ones. We brought my sister's cats in every now and then so they could start making introductions. It was a long, slow processes. For the most part, they all get along. However, they still have spats from time-to-time. Seymour and Grayboy have become best buds. Molly and Cinnabuns have decided to pretend each other doesn't exist.