Sorry for the disjointed nature of the guide, but it originally started life as a Wishlist item.
You should also read this post:
https://getmusicbee.com/forum/index.php?topic=22674.0, as this is what started me trying to sort this out.
Oh, man, I can't make it work!!
I'm trying a lot of things but non of them work, it's so frustrating.
There's something in your post that's obvious for you and apparently not so obvious for me and my knowledge.
Sorry to waste your time, Bee-liever.
If your gonna give me praise like this:
Bee-liever has done it again, this guy is just brilliant
don't ever worry that you're wasting my time
OK. Christo (and others) I have been able to use the Covers view to group my VA releases into release/genre types and sub-group them by release series:
VA Christmas Albums and Album Series

while also grouping Artists into Studio Albums, Live Albums, EP's, Singles, etc

As shown in the other linked thread, I've used the Grouping tag to hold this info.
VA Christmas album

VA Christmas album Series

Standard Artist single

I've then used two virtual tags to split up the Grouping tag:
Group Sorting$If($First(<Grouping>)="G6",$Split(<Grouping>,;,1)$RSplit(<Grouping>,],1),$First(<Grouping>))
Release Group$If($First(<Grouping>)="G1","Studio Albums",$If($First(<Grouping>)="G1a",Soundtracks,$If($First(<Grouping>)="G2","Live Albums",$If($First(<Grouping>)="G3",EPs,$If($First(<Grouping>)="G4",Singles,$If($First(<Grouping>)="G5","Compilation Albums",$If($First(<Grouping>)="G6",$IsNull($Split(<Grouping>,;,4),$Split($Split(<Grouping>," [",1),"; ",2),$If($Contains(<Grouping>,ⁱ)="F",$RSplit($Split(<Grouping>,ⁱ,1),"; ",1),$Split(<Grouping>,;,4)": "$RSplit(<Grouping>,ⁱ,1))),"Undefined Sources")))))))
so that the info can be used in my custom sorting:
Album Artist/ Group Sorting/ Release Sort Index
and my 'Group By' (Sort Album Artist) and 'Sub Grouping' (Release Group) settings.