Seeking kittycat psychology advice

[Voice for Peace]

I have 3 cats (all neutered/spayed):

One is 12 yo female. I got her 1-1/2 years ago from my daughter, who had her for about 3 years. Her original owners gave her away because they were having a baby or something like that. (When she came to live w/daughter, she became an indoor-only cat. Before that she was indoor/outdoor.) She's my main concern.

Her life with my daughter was ok but I suspect stressful. She apparently hid a lot, and threw up her food all the time. When she came to me she was very skinny and "testy." I changed her food and she stopped throwing up, became more sociable and affectionate with me.

After I had her for a few months, I (foolishly) decided she needed another kitty for company, and adopted a male kitten. Ah, woe: she hated him from day one. She hid for a while, and whenever she encountered him would hiss, growl, swat at him. He was like: whaaa? huh? wtf??

So, a few months later, I adopted another male kitten, as playmate for the other.. and to relieve some of the pressure on the female.

The two boys get along great. Very playful, affectionate. Both less than a year old. But she hates them both. There's some combination of fear and aggression towards them. Growling, hissing.

Once in a while, when I am playing with the two boys on the floor, she sits nearby. She seems almost sad at those times, I don't know if I'm projecting.
.........

Recently I had to make them all be inside-only cats. This is ratcheting up the tension here. And she seems needy towards me, sitting in my lap about 10 times more than when I was allowing her outdoors.

I keep wondering: what happened to you, kitty? My sense is she's been traumatized, one way or another, that she has so much fear & hostility towards the other cats -- who totally leave her alone, if she lets them.

So.. any expert cat psychologists out there? Or people who've dealt with anything similar? I wish I knew how to heal whatever is making her so miserable. She was much better when she was able to be outside all day, but that's not an option right now. She's pretty sweet when she's by herself -- but very possessive of me now -- and really mean and nasty bitch whenever the boys are in sight. I'm giving her lots of love and affection, but it's a challenge.

I know they're all adjusting to the indoor-only change -- it has only been a few days that I've stopped letting them roam during the day (deer ticks and coyotes).

Any input most welcome, thank you!

[Why Syzygy]

1. Awww...that's so sad.

She may just never be happy with them. My former roommate, whom I helped adopt two kitties about nine years ago, has since had one run away. He adopted another second cat, but the one left was never happy and very hateful to the new kitty. So, he has since adopted her to someone else, leaving him with the one who believes he owns the place, and evidently he does.

All I can think is just give her lots of extra love and make sure she knows she belongs. Do you live alone (humans)?