what is the problem? when I click file → export → audio mixdown I can select single or multiple. Everything in the mixer it is laid out perfectly - I just tick what I want exported.
if I want all my group channels I tick the “group channels” - if I just want the drums group channel I tick that
I assumed that the ‘mutiple’ selction, and the channels I selected meant that Cubase summed those selections to a single file. It’s just differnent from Cubase 9 I guess, e.g. the naming scheme is grey out where normally I’d be able to tell Cubase to name the exported files according to the track/groups names.
The layout/system for this has changed but it is just as extensive as it was and slightly better laid out I think but does require attention to detail on your part.