Advice on introducing a new cat

[Leeds157]

I have two bonded sisters (both 2 years old) who we adopted at 6 months. They’re confident with us—definitely not lap cats, but they like being near us on their terms (following us around, sitting next to us, etc).

When we have visitors over, they tend to hide.

I’m considering adopting a 5-year-old cat from a local rescue, but I know it might not work out.
Has anyone successfully introduced an adult cat into a home with an already bonded pair? If so, how did it go?

And if it didn’t work, or if you have any general advice, I’d really appreciate tips on introducing a new cat into a household with resident cats.

I’ve started looking into Jackson Galaxy and scent swapping already, but keen to hear real experiences too.

You will get a lot of advice about scent swapping, keeping them confined to separate rooms, Feliway etc. I’ve done it successfully and tried all those things but in the end, I think what worked best was giving them space and time to sort it out between themselves. I think separating them was counterproductive in a way because they could smell each other but not see each other. It took a week or so but they ended up in a position of grudging respect and tolerance (the older two) and one-sided adoration and amiability (the younger one, who had an unusual love of his fellow cat and living beings in general)

We had to reintroduce a litter mate when DMIL went into a home. We used a puppy crate for the "new" cat, as large as you can get (ours allowed for food and a litter tray) and then just give them time to get accustomed to each other