TYPO3 Core

You can do this locally by just changing the database. Also you can nest groups to have fewer groups to include.

You can of course push a change to gerrit or start a discussion on the core mailing list, whether this should be changed. To me, this sounds like a feature request. Best thing would be to move to MM tables instead of having those CSV lists.

Patch set 2 for branch master has been pushed to the review server.
It is available at https://review.typo3.org/21593

Patch set 3 for branch master has been pushed to the review server.
It is available at https://review.typo3.org/21593

Patch set 4 for branch master has been pushed to the review server.
It is available at https://review.typo3.org/21593