Which is better for multiple Volume releases?

[Antichrist01]

Question as in the subject.

Release group series
https://musicbrainz.org/series/71c8ace5-5b5b-4f3c-b4e6-82278f394af0

or

Release group by Various Artists
https://musicbrainz.org/release-group/70374851-b009-4631-9594-e8a268aa8392

[jesus2099]

Release group series.

The second example, a release group of releases with no common tracks, is wrong.
It does not follow the release group definition (variations of the same release).

[aerozol]

edit: I misread the question… definitely use series!