Special group for all entities not in other groups

Hi, I would like to have one group for every room with the corresponding entities, and one group for “all others”, to make it easy to spot entities that have not been set up yet and gather all non-important entities. By default, it seems like the “home” group shows all entities, and if I make a new default_view, it hides all non-configured entities. Is there a “default group” all entities end up in if not configured otherwise?