Style / Release Group
What should be grouped together?
Release groups should be used to group variations of the same release. The following are examples of things which should normally be grouped together in the same release group:
_ The original release_
None of which exactly answers your question, as far as I can see.
The understanding I have is that if the set of recordings in the releases are substantially the same then they will be in the same release group.
If my understanding is correct then I'll look to edit the wiki version of Style / Release Group to include that criterion and then ask for the Documentation to be revised accordingly.