I found JRiver a complete dud.
The ability to have Folders and Sub-Folders, a la iTunes, is nonexistent.
Grouping artist albums is even hard - they have to be 'tagged' properly on importation (I take it this means the metadata in FLAC has to be the same. eg Beatles is not the same as The Beatles or Beatles, The)
I became so tired of trying to make it do what iTunes does that I gave up and asked for a refund - They decline to give me one!