I've done it. It takes time. At first we put up a door (bi fold) so the cats were separated from the dogs, and across the other doorway we put in a swinging door so the cats could fit under and access the dog part of the house but also escape to the cat side if they wanted. The dogs were not allowed on the cats side. We have a large fenced yard, so I didn't feel too guilty about taking a little house space away from them.

Then when I got Hanna, I closed the access because she was a squirrley little kitten, and Bandit the dog is old and grumpy. She was separated from the dogs until she matured a little, but now all animals have full house access and it is going OK. Everyone gets along, and the cats respect the dogs' space. The dogs are even a little timid around the cats - we don't allow them to chase, harrass or growl at the cats. I learned the hard way that even a little dog bite can be life threatening to a cat, so be sure to keep a close eye and make sure there is no incidents of a dog snapping at the cat. A dog can easily kill a cat with one snap, so that is why I was so careful.