You can only delete a VLAN Group if none of the VLAN segments in the VLAN Group are currently being used by a network.
To delete a VLAN Group:
In the Hardware view, select the Hardware tab.
In the navigation pane, select Resources. In the management pane, select the VLAN Groups tab.
Select a VLAN Group in the table, and click Delete.
Click OK to confirm the deletion of the VLAN Group.
The VLAN Group is deleted.