Transferable mouthpiece and speakers; advice ?

Friend of mine is looking for an Autocom system or similar which enables him to do all the standard things that the Autocom does but most importantly, he's looking for helmet speakers and mic that can be transferred to different helmets, i.e. that are not permanently fixed in the helmet as he has a number of different pillion riders with their own helmets...

Any ideas on manufactureres or systems available ??