Preferences / Favorites and Recent / Label Assignments, add a new Label Filter:
This will cause extra disk access, so be sure it's something you really want/need.
If you only want/need it in certain places, you can create the label as part of a folder format instead of as a global label, so you only suffer the extra disk access where you need to.
(Empty folders don't really cause any problems so I often wonder why people are so worried about them. For me, Ctrl-K to calculate folder sizes, then sorting by size, is enough to clean them up on the rare times that I need to.)