To access a Group options, environment must be stopped then right-click on a Group. Right-clicking on an existing group gives access to 5 options:
Hold/Release: Block/Release the existing setting
Insert: Inserts a new group before or after or creates one if it does not exist yet
Delete: Deletes the group and the selection rules it contains
Generate: Generates the list of objects to be part of the perimeter
Settings: Access to group management settings