Ages ago I brought Cassy and Sassy to my parents home when Livvy was their cat. They didn't get along at all. (Massive understatement, believe me.)

We took the three of them in to a groomers to be groomed/ bathed, etc. They got along quite well afterwards. Not sure if it was becaused they smelled the same, or felt they needed to consolidate against a common enemy. [That was when Livvy became 'Catta non Grata' for those of you who remember the previous post...] Perfume would be a cheaper option.