To view all notification groups for your organization, click on the "Monitoring" tab, and select "Notification Groups".
This screen has the following columns:
Name - the name of the notification group
Description - a short description of the notification group
Members - the number of users assigned to the notification group
To add a new notification group, simply click on the "Add" button at the bottom of the screen. To edit a notification group, either click on its name, or select its checkbox and press "Edit". To delete one or more notification groups, select them using their check boxes (hold down Shift to multi-select), and press the "Delete" button.