Nice to be on the forums. I have just started an introduction process with my indoor female cat (7 yo -- I've had her for just about 2 years) and my father's two outdoor/indoor female cats (both about 5 yo, sisters). This is taking place at my father's house, so the turf belongs to the sissies. I'm so scared that this will go badly! For now, I've been taking it very slow (we're only on day TWO!). I'll need lots of advice and support!