before i try it and come unstuck did i see previous posts saying its impossible to record subgroup mixer moves?

is that true? if not how do i do it?

and if i can't how do i get a final mix that i can export? I want the backing as subgroup so i can fade up and down when the vocals come in. i've got the backing balanced as i like and one fader moving up and down is the ideal way to get a final mix