If you can not separate them at all then bring kitten in in her crate. Set the crate in the middle of the room where the cats will spend the most time in, and let your resident cats come over and sniff the kitten through the door. And, of course, visa versa. Then you can open the door slowly and see how they do with the baby. I would still find a spot to separate them at night when you can't supervise.
If you see an adverse reaction then you will have to find some small area for the kitten, even a large closet will do, and do proper introductions.
My favourite site is: http://www.squidoo.com/multi-cat-management
There is so much useful information there you will be reading the whole thing!