When I first started in rescue, I used to have the kitties in Pet Smart. We had 3 semi-feral flood kitties: Gretchen, Donovan and Amber. We kept them together in the largest cage so they would feel safe. I noticed that Gretchen wasn't coming out with Doovan and Amber. So we decided to separate them into two cages with Donovan and Amber in the top and Gretchen on the bottom. I would clean both cages at the same time. When we were done cleaning the cages that meant play time. I took Amber & Donovan out and left the cage open for Gretchen to join us. It took some time but she eventually caught on that if she wanted attention she had to come and get it. I also gave her alone time. I would open the cage and let her come out. She could explore the adoption center and meet the other cats.
What helped get them adopted was a reporter happened to be in Pet Smart and was looking at their cage card. I told their brief story of how they were caught in the flood and a good Samaritan helped feed them. The reporter did a story on them and the applications came in. A lot of people thought that we should have adopted all 3 of them out together. That's a lot to ask of an adopter. We did adopt Amber & Donovan out together. Gretchen found a home of her own.
Another case we had was when 2 cats bonded while in the adoption center. It was unusual but Katy & Inky were determined to stay together. I was adamant about keeping them together. When I would walk Inky on a leash around the store you could just see how upset Katy got. I tried walking her on the leash and she wouldn't have it. Here again, people would say "But Katy likes me!". Katy likes everyone but it doesn't mean that she would have been happier being alone.
In both cases it took over 6 months to get them adopted out. In our area, adoptions can be a very seasonal thing. Lots of people go on vacation during the summer and don't want an animal until after they come back.
My point is you have to trust your instinct on this. At this stage I would try separating them and see what happens. I always valued what our volunteers had to say about our cats. However, sometimes you just have to try something new. You have nothing to lose. This might be exactly what Hannah needs. It will take a very special adopter to work with her. She might need long-term one on one foster care. Is there a foster that is willing to work just with her? Don't give up on her. It will be worth it. Replace the word problem with the word challenge. It changes the perspective.
Best of luck,