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

Access Controls

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.