My partner has 3 and I have 2 - we are planning to buy a house together next year, and our biggest worry is the cats getting on!
Are there any good websites or books we can read for ideas on how to make it a smooth process?
Our ideas so far are to create cat runways across the tops of the walls with shelves, so they have as much territory as possible indoors. Create at least two exits/entrances with cat flaps coded to their own microchips (my 2 using one entrance and her 3 using the other), introducing each other's smells in the months leading up to the move (rubbing towels on them and swapping over, etc - they are already aware of other cat smells due to us visiting each other but a more concerted effort), once we've moved in, the cats are kept in separate areas of the house (this can't really be clearly planned until we know which house we're getting, the layout, etc), slow introductions to one another (not sure how we are going to manage this, as all 5 are used to coming and going out of doors as they wish, we may have to work that in shifts??)
I'd love to hear anyone's success stories, as well....