New Kitten/Old Cats

I brought a male kitten (Tommy) home Saturday to my 2 female cats. I live in a one-bedroom apt. so I really can't keep the cats separate. Ella (9 yrs old) is the alpha and also the mother of Scat (7 yrs old). Ella was scared of Tommy at first, and Scat hissed and swatted at him. Now Ella is growling at Scat, and they occasionally erupt into fighting with each other, growling, hissing, awful sounds (I didn't get any sleep last night!). I have paid a LOT of attention to Scat and Ella, and I've rubbed a cloth on each of the their cheeks and have gone back and forth. I haven't really put Tommy into the mix. It is so disheartening to see them fighting with each other. I don't know what to do. And they both are still hissing at Tommy. Help!

You really need to keep the new kitten in the bedroom or possibly the bathroom. Introductions need to be done slowly with lots of positive reinforcements (toys and treats).

So even though they have all had access to all the rooms since Saturday, I should put the kitten back into the bedroom with the door closed? The problem seems to be between the 2 female cats - horrible sounds are coming from Ella...like a pig snorting! And I know that if I do that, Scat will be outside the bedroom door crying to come inside the bedroom when I'm in there. It's killing me seeing my 2 girls fighting like this. Any advice is MUCH appreciated!!