Details are in the Feature Request topic below:
EDIT: After closing and relaunching Roon several times, it appears that the issue is not grouping different album versions causing the newly grouped tracks to separate again, but instead the issue is giving a name to the group that is the same as the name of the first track in the group. So “Sweet Thing: Sweet Thing” must become something like “Sweet Thing Medley: Sweet Thing”. Once that is done, different versions of the album can be grouped and the created track grouping in the album(s) will remain intact.
I still think the user should have the freedom to name the new “work” anything they want, regardless of the name of the first track in the group.