can you connect additional cdj's to a xdj rx?

it has 2 extra inputs, so yes
can you use them at the same time with the decks, no!

Sure you can use them the same time.

But as the XDJ-RX has only built in a 2-deck mixer just two decks (of any input) can go on air simultaneously. You can select the input with the input select switch.

Could I use the Rx as 2 extra decks on djm 2000 nexus? I have 2000 nexus 2000
:)

@Vittoria > Yes and no... if you're using it with rekordbox DJ, yes, otherwise the output from the XDJ-RX is a mixed-output, meaning you would be sending the master output from the RX to an input channel on the DJM, making it a bit awkward.

@pulse I am kind of using the rekordbox dj, for 5 weeks had issues, finally today after updating my dim 2000 nexus after downloaded the driver for 2000 nexus it has worked (haven't really played on it) but already felt better specially on bpm instability. It is not so important, but would be fun to add the RX1 to djm 2000 and have 4 decks.

@Vittoria > If you use rekordbox DJ, you can do that because the control can be from the XDJ and CDJs with the audio all being routed to the DJM-2000.

Can you connect a Ddjsb2 to Xdj Rx2?

Sure, just run the master output from the SB2 to AUX or one of the line inputs of the RX2.