Hey John,
I haven't fully thought this thru yet, but I think that if you just set up the streaming ports on the NAX units to a separate switch and then use the other/non-streaming ports for control on the main network - basically a hardware wall between the two communication types...
This is not the ultimate solution, but it could get you done for now...
Tom Brady (not the Quarterback!) at Crestron would be the guy to review this with, Send me an email if you want his contact info...