Ability for All Users to send to All Online Users

In the openfire admin tool we can send an administrative message to all online users: http://i.imgur.com/HLTswJb.png

This is brilliant, however when a user responds to the message they get, this message in turn gets broadcasted to all online users. Is there any way to restrict this to administrators only, the same as the broadcast plugin?

There is the “plugin.broadcast.allowedUsers” key.

The documentation reads:

Sets the collection of addresses of users allowed to send broadcast messages. If the collection is empty, anyone can send broadcast messages.