Hello,
Some CDs are sold in boxes, example:
Les créatures from Philippe Catherine includes:
= Les Créatures
= L’homme à trois mains
which are two original CDs.
I don’t understand how to add “L’homme à trois mains” original album (1 CD) to the release group.
Today, I also added a new CD box set in MB, pretty the same situation, as adding original CDs is needed:
Please advise.
Your second example is a regular compilation with its own release group, it is good.
For your first example, it seems that individual albums were never sold alone so the single CD releases and separate release group are wrong, if it is so.
If A album, B album and A+B bundle do all three exist, then there should be three release groups.
If it was always sold as A+B only then there should be only one release group and no single CD releases.
If it’s sold together, it’s one release for MB. If they’re also sold separately, then those should be added as separate releases in separate release groups, and linked with the included in relationship (so the Gainsbourg release can be linked to the four original RGs).
Got it, thanks!
In fact, it is even more complicated (and interesting).
To take the example of Gainsbourg, each CD in the box is an official album sold separately and has it own label ID (but no bar code). Each CD was sold separately as an Album, so it should belong to a release group. Today, each CD may appear in other boxes. On box is called in French “Tous les albums studio de Gainsbourg”. Therefore, each CD is a release …
And the numbering of disc ID proves it.
So I created a release inside a release group for each album:
532 648 - 6 => https://musicbrainz.org/release/d99fa0aa-097f-4ab0-875a-749783642e36
532 648 - 7 => https://musicbrainz.org/release/10408d1e-90c9-4f1d-a0f3-e888c8029d9d
532 648 - 8 =>https://musicbrainz.org/release/747d9741-2745-4c57-a2be-718aa52985b9
532 648 - 9 => https://musicbrainz.org/release/4e01d8d8-42d3-4273-ab5f-7f90a512fbac
Now I will link those releases with the release pack with bar code.
Still lost … and need help.
How can I link the four new releases to my “4 albums originaux” from Serge Gainsbourg?
I tried to add a relationship from release A to release B but it not work.
Can you describe more precisely using my examples.
This is a release group relationship, currently. So you need to link the two release groups: Release group “4 albums originaux: Vu de l’extérieur / Rock Around the Bunker / Aux armes et cætera / Love on the Beat” by Serge Gainsbourg - MusicBrainz and whatever the one for each album you added is 
It uses release groups, rather than specific releases, so it also applies for cases like “these two albums were re-issued together in a 2xCD pack a few years later” even if it’s not just literally a box with the same old CD inside it.
You should not add the parts of boxset as separate single CD releases, though, only as a big multi CD release.
Unless, of course, they’ve also been released separately!
Of course but in this case it seems they created the parts as standalones, by reading their annotations where they wrote those (with this catalogue, bar code, etc.) were only released as part of box. cf. this post for links.