James Kennedy (one of our Tech Support guys in our UK office) recently finished an example of how to have two PageMatrix Command Centers connect to a single NioNode.  This also shows how to have a Command Center and X-Controls connected to single NioNode.
You will find it in the usual place...
http://downloads.peavey.com/mm/index.cf … _Materials
Great job, James.  We are open to other members of our Forum adding examples.  If you have one, send me an email.
I have also recently added to the Class Instructor details for the SPA (X-Controls) and External Control (added Control Aliases to the Ballroom controls).  For the External Control, be sure and get the a new spreadsheet that is in this folder called "Sample External Control Matrix--Class Instructor--*.  This is what I give the External Control programmer listing the Control Aliases.
Another new spreadsheet is what I give to the client to coordinate user names and passwords.  Hopefully, you will find this helpful.
Thanks,
Scott