We have two cats who are indoor/outdoor, and just got a 9 week old kitten. The two older cats have access to the outdoors through a cat door that leads to the sunroom, and from there through another cat door to the outside.

At the moment, the kitten is being kept in the office to adjust to new surroundings, and occasionally is let out to explore parts of the house and have all the cats adapt to each other.

I'm trying to find a way to keep the kitten safely indoors until she's a few months older, while still allowing the other 2 access to the outdoors (as much as I'd like to, making them all indoor-only cats is NOT an option).

Once the cats are all used to each other and the kitten is allowed free reign of the house, she's bound to stumble upon the cat door eventually... and I certainly can't realistically watch her like a hawk and follow her through the house day and night.

Any suggestions?