Dr. Tajunnisa M
Initially the new pet should be kept in a separate room for a few weeks. As the cats produce their own scent which they use for territory marking along with urination, it's hard for old cats to accept the new ones. During this separation period, you can switch the cat's bedding on alternate days so that they get used to each other’s scent. Get them toys separately and swap between them. Give them playtime for one hour together under your supervision. Give them feeding and water bowls separately.