Well, lucky you it already does have separate parameters for each button! Check out the GPView example model included in the example models zip file
OH I never ended up using the included sample because I rigged a different asset to respond to the analog stick's x/y, I probably shouldn't have skipped the tutorial. 😅
I genuinely don't know how I didn't see the prompt at the bottom of the screen that said "Show extra parameters [TAB]" and now that I can see the individual buttons I can't wait to experiment with more!!