Groups and multidisc albums

[swdick]

I use the Group.default={Composition} trick to see Compositions as separate items on an Album (and not the tracks). Works perfectly, except when the composition is on multiple discs.
I use , disc<n> extension after the Album title. The log shows 2 types of errors:
Error: group spans multiple discs:
Error: group contains tracks that aren't consecutive:

Do I have to create a seperate Group tag by hand to every disc of the compostion?
I read the instructions but the explanation is beyond me.