OLAH Stuart. Can you explain how do you will connect the RMX-1000 to your XDJ? Do you Have the possibility to use a recorder unit external on radio station?
The XDJ-RX has two USB ports, with Deck 1 enabling playback while Deck 2 allows playback and recording at the same time. So two DJs can perform together and record their set, without sacrificing an input.
I haven't now the units physically to confirm that to 100% but here you are different options to try:
1.- Connect RMX-1000 to Deck 1 & one USB or HDD with Music to Deck 2. You have this USB port to play/rec.
2.- Connect the RMX-1000 throw the send/return option ( XDJ-RX master 2 to RMX Input and RMX Output to phono/Line1 input). This connection will be like a subchannel to record the RMX FX with level of fader 1 if you select the phono/line 1. But you only can put the RMX Efx to tracks that sound on deck 2. In fact, you only add the RMX EFX to HAlf tracks you play in that mode.
All is more easy if you add an additional mixer or an external recorder
Please, let me know your experiments with it ;-)