Tagging classical music

[gnomus]

Tagging Issue:

I thought I'd post in this thread rather than starting a new one. I cannot work out how to achieve a tagging objective:

Wagner's Ring conists of 4 operas, three of which consist of three Acts. The operas, in order, are: Das Rheingold; Die Walkure, Siegfried; and Gotterdammerung.

I have several versions of it on CD. ('.m too embarassed to say how many!) I would like to achieve the following:

1) In my CP, under Composers, I would like to see a list of "Compositions", one of which is "Der Ring des Nibelungen".
(I have been able to achieve this)

2) When I click into the "Der Ring des Nibelungen" album (?container), I want to see a list of Albums. Within Albums I want a list of each single version of the Ring that I have ripped. For example, I want one entry for "Ring; [Solti - Vienna -1958-65]" and one entry for "Ring; [Barenboim - Bayreuth -1991-92]".

It's only when I click on one of these Albums that I want to see the individual operas making up each Ring - Rheingold, Walkure and so on.

I have ripped each Ring into a separate folder on my NAS. Within that folder, I have another folder for each of the four parts of each Ring (Rheingold, Walkure ...). I have tagged all 4 parts of the Solti Ring as belonging to the "Album" - "Ring; [Solti - Vienna -1958-65]". I have done likewise for the Barenboim Ring. Both the Solti and Barenboim Rings have been tagged as "Composition" - "Der Ring des Nibelungen"

I thought that this would work, but what happens is that when I open the "Albums" container in my CP I see four entries for each of the four parts of the Solti Ring.

I am not sure why this is. Is there something obvious that I am doing wrong? Is there a better way of achieving what I want to achieve.

[EDIT:]

I should add that I have used "Groups" to tag the individual operas - so I have a "Rheingold" Group; a "Walkure - Act I" Group, and so on.