I too am a JRiver user -- it's one of the only solutions I've found that I'm happy with. I found the best way to deal with my classical collection is to add my own meta data.
I add the following tags:
WORK
ERA
ENSEMBLE
and a few others.
Doing so, I'm now able to build menus like:
COMPOSER > WORK > ENSEMBLE > CONDUCTOR
Stravinsky, Igor > The Firebird > Montreal SO > Dutoit, Charles
or
ERA > GENRE > COMPOSER > WORK > ENSEMBLE > CONDUCTOR
Romantic > Symphonic > Mahler, Gustav > Symphony No. 3 > etc.
Works beautifully.
