Ok here's what my setup looks like.

steering wheel buttons > fusion brain > head unit

Now to keep my steering wheel controls actually working I have to have to keep the steering wheel control hooked into the head unit. I'm sure there's a way to do it without them being hooked up to the head unit but I don't know how to do it.

Anyway, after my fusion brain receives the signal from the steering wheel controls, I'd like to place something in the line that would keep the head unit from receiving the signal. The idea is to be able ot use the brain, but not have the head unit respond to the button presses. I hope this is simple haha.