an exception based on disc-count (number of total discs)
I am assuming total discs in an album (not total discs for an artist).
And it also depends MP3 or FLAC or
MP3 total discs is normally part of disc number eg 1/
3In FLAC its a separate tag "Total Discs"
You would need to create a custom/virtual tag to read the tag in FLAC and create an expression to read the number/s after the
/ in MP3
If you do mean total discs for an artist, I'm not sure how you'd go with that one. I know MB keeps tabs on how many tracks per artist, but don't know about albums