Are the Nexus mark 2?
I have a DJM900 SRT & 2 CDJ 2000 NXS. To use it in performance mode I need to plug in my SP1 into a hub. That said IF you have Nexus mark 2 you should be able to use the SP1 through one of the USB ports on the CDJ
i think I've everything in Link no Ethernet
in Export mode I use Ethernet and no SP1