I'm in the same position as you - except I have one old lady, and two young boys. I got the boys in May. It's been a nightmare. The old lady cat picked a spot behind the chair and wouldn't come out. She stopped going to the litter box because she might have to come across one of the boys, so she started going behind the tv. All the boys have to do is look at her and she's growling and screaming - which makes them even MORE interested in getting a rise out of her. After many nights of waking up to screaming cats I finally started taking the old lady to bed w/ me. Then she peed on my bed on night because she wouldn't get off to go the the litterbox. That was the last straw, and I separated her out into another room.
The separation made my life easier in some ways, but here I've got an old lady momma's girl w/ CRF that's been banished to another room, all by herself. That wasn't working. I got another litter box and put it in my bedroom, and every other night shut her in the room with me and the dogs, so she'd at least get to sleep with me before being locked in the other room again. That was better, but still wasn't working. The old lady may be hysterical and bringing this all upon herself, but she's old, she has CRF, and she lost her two brothers and gained two interlopers. It's not like I can reason with her, so I have to work with what I've got. I asked the vet for some anti-anxiety meds, and she sleeps with me almost every night now. It can take up to a month for the meds to reach their full effect, but so far she seems.... better, and it's been a few weeks. Still not great, but they can at least now (at times) walk into the room without her pitching a major fit. In FACT - one of the boys was able to jump up on the bed and lay down next to her today and she didn't make a peep. She DID give him the stink eye, but still.... Although he is the one she seems least concerned with.
She's with me mainly at night in bed, and separated off into the other room when I'm not around to "supervise". I'm hoping to try expanding her area to the rest of the house in mid December, and see how it goes. It's really horrible. I can't give the new ones away, and I obviously can't get rid of her either. I just wish she didn't have to make it so incredibly difficult.
Here's the photographic evidence of her quiet stink eye today - she's the black one: