Unixgroupadmin -- customizable group self-service on /etc/group

 Unixgroupadmin provides a command "group" which ordinary users can use
 to add new groups, add members to their groups, part groups, and manage
 who is responsible for a group.  Who is allowed to do what kind of
 operation is customizable by a global configuration file.
 .
 Unlike most other group self-provisioning systems, Unixgroupadmin
 operates directly on the standard unix group database, /etc/group.
 This means that you can use it as a drop-in addition in your system,
 because it will not clobber any group management by traditional means
 (such as addgroup, groupadd and vigr).
 .
 As Unixgroupadmin handles /etc/group, the "group" command is installed
 SUID root.

Installation

Just run "make install" as root.  By default, it installs in /usr.  To
override this, run "make PREFIX=/usr/local install".

Usage

The actual user interface is the "group" program.  See "man group" for
details.