Try using a MacroCommand.
The reason for one Command per Notification has to do with the mechanism used for executing Commands.
The Controller is registered as the observer for the note, and when its ececute method is called, it looks up the class to instantiate as in a map keyed by note name.
Now it could maintain its own observer list and all that like the view does for Mediators but it isn't really worth the complexity. MacroCommands are generally an acceptable solution.
And no, Mediators do not share this limitation. You may have any number interested in the same note.
-=Cliff>
PS: to be 'less verbose' I was going to leave it at the first sentence, but thought it might be rude.
The challenge is to use as much verbosity as clarity demands, but no more.