Hello JSW W.,
To be able to distinguish which command is clicked when NCommandBarsManager.CommandClicked fires you can set and then check the ID property of each command in command bars manager. This approach is demonstrated in Command Bars -> Persistency example from example application provided with installation package.
The only way to determine the position is described in this topic http://community.nevron.com/Forum/shwmessage.aspx?ForumID=2&MessageID=3188.
Regards,
Angel.