Flash only option for fader buttons

I often have LED lights with all their properties (eg color, zoom) recorded to a submster that I then set to Int Master so that the NIPs don't change when I bring up the fader. However, by doing it this way, I am no longer able to use the bottom button as a flash key, so if I want to use it as a flash key, I have to record a second sub setting all the NIPs to full in the background so my main sub only contains intensity data. I would like to be able to set the bottom button to some sort of flash only option so that even if a submaster contains all sorts of parameters and is set to Int Master, that button behaves like Go/Flash would on a sub containing only intensity data.