TL;DR: In the Artwork view for files in the main panel, is there a way to group tracks first by format (.flac or .mp3) or path (/music/flac or /music/mp3) and then group again by disc number?
Background:
I essentially have two duplicate libraries; a large .flac collection (stored in /music/flac) that has also been converted to .mp3 (stored in /music/mp3). In MusicBee, I have a filter set up based on path so I can have stuff from /music/flac and /music/mp3 in separate tabs, as well as a third tab which combines everything from both paths.
I use the Artwork layout for the files in the main panel, with tracks grouped by disc number.
Previously, in the tab for the combined filter, a given album would have each track in the list "duplicated", such as Track1 (mp3), Track1 (flac), Track2 (mp3), Track2 (flac), etc.
For now, I've settled on adding "Path" as one of the global criteria for grouping (in Preferences > Sorting/Grouping), so that the .flac and .mp3 albums simply appear next to each other.
What I would like to do is be able to remove "Path" from the global grouping criteria so that each album is displayed a single time in the Artwork view, but add an additional grouping criteria before Disc# to group by path so that the track listing is separated properly, first by format and then by disc (see quick mock-up below).
I've played around a bit with different virtual tags/sub-grouping options for the Artwork view, but haven't come across something that will work for what I'm trying to achieve. I'd appreciate any help/advice that any of you folks are able to offer.
Thanks!