use_group(), use_me() filters group behavior beforehand.
ControlGroup::set_group_value() lacks context to make the decision itself
and should always apply to the group (regardless of active state):
InverseGroup allows to override both: inactive predicate and inactive group.
This needs testing, particularly since RouteGroupMember::use_group()
is no longer used and was superseded by RouteGroup::push_to_groups()
c29568f4c5