The managers of a group may choose to create one or more subgroups in that group, as distinct from creating additional separate groups. With a few exceptions each subgroup of a group has the same features and controls as any other group, including the parent group.

It is those exceptions which matter when considering whether to make a subgroup to an existing group, or a separate group.

Related membership

Subgroup members must be members of the parent group

Direct Add

Open or Restricted subgroup membership

Related addressing

Subdomain addressing

Legacy addressing

Examples

Moderators' group

A common desire is to support better communication among the management of a group. In Y!Groups and other email lists this is sometimes achieved by creating a separate group, whose membership is restricted to just the moderators and owners of the primary group.

This is a natural use case for a subgroup.

PTA group

Primary group is all PTA members, subgroups for board, teachers, school admin, and students.