Dustin Pieper

I don't believe so, I'm afraid. Since the material library can only define materials on the project level and not the model level, any variable used to modify the materials will by definition affect the whole project. I'm pretty sure that's why they force you to use a global variable when defining material parameters.

I think your best bet would just be to define unique materials for each model and have independant variables for each of those, although that can really muddy up your parameter range long term, which could be somewhat organizationally nightmarish. It would at the very least lead to some pretty ugly legends on your plots, unless you are extra judicious with setting nominal variables in the plotter. At that point, it might just be better to define multiple projects. 

Good luck!