Thanks a lot guys. What I wanted to do was have the texture of a brush change to another. The only problem was the bush in question is a brush based vehicle. the texture would have to actually change as opposed to being disable and having one with a different texture appear in its place.
It seems that it is currently out of my league, at least until someone comes up with a "Changing textures tutorial for dummies (Neo_Jimmy); explains how to do everything in a nauseating amount of detail".