NFS Services Administrator's Guide

Configuring and Administering NIS+
Administering NIS+
Chapter 5 259
To add or remove members of an NIS+ group, you must have modify
permission for the group.
You can use SAM (System Administration Manager) to add or remove
members of NIS+ groups. To run SAM, type sam at the HP-UX prompt.
For more information, see the man pages nisgrpadm(1) and sam(1M).