I cooked wheat berries for a salad and used organic vegetable broth for the first time instead of water, and they came out mushy...

wow, did you cook them for 10 hours or something? I've never cooked mushy wheat berries and i cook them a few hours, so i am surprised. the cereal or soup suggestion is a good one for using them up. the type pf water or broth should not play into causing mushiness.

I've found that recipes tend to over cook wheat berries. I do an overnight soak and a quick boil 10? minutes just to get rid of anything "bad".

You can always use the mushy ones to make more of a porridge type thing. Add milk/cream bananas, etc.

I agree with the above and I'm thinking you used too much broth.

Well, it all depends on how much the mushy-ness bothers you (and how mushy they are), what recipe you're using and how important the wheatberry element is. Can you tell us what recipe you're using?
I don't think that the broth would make them mushy, unless perhaps somehow it's because of the salt content of the broth. Purely brainstorming though.