From MusicBrainz Wiki
Style for titles of split releases
If a release is a SplitRelease by two or more artists, the title should be named as follows:
- ArtistA / ArtistB
- This is a ProposedStyleGuideline.
- ArtistA / ArtistB / ArtistC / ArtistD
- Kyuss / Queens of the Stone Age
Note that this is space, slash, space!