[itsme]

Reggoboy's request is IMHO too specific to justify such huge changes.
BUT: it would absolutely make sense to implement meta data for groups. They should be flexibly usable for users' individual needs, similar to custom and custom2, additionally with configurable names.
I can organise my workflow for many gigs with various line-ups without problems. Reggoboy could use the meta data of setlists to store whatever he thinks to need.
My personal use cases for meta data for groups would be:
I use albums for fakebooks. If albums had meta data I would configure them to store e.g. author, publisher, year, ISBN ...
European copyright depends on the year of death of all authors. If composers had meta data I would use them to store the date of death and a different display name and sort name.