Certain users would like the ability to block external dialing *into* cloud accounts. So for instance being able to make a user *only* accessible to the internal cloud group. This user would not be available by dialing over the PSTN number and extension. They could still dial out freely to meetings and other users, and members of the user's cloud group could dial them, but external users could not reach the user via the extension. These users consider the Do Not Disturb function a bit too restricting. This feature would be managed via the admin console as well as letting the user manage it themselves in the client.