So I have the CDJ setup and here's a way to split the fader start signal.
You have 4 CDJ 900/2000/2000nexus and either a DJM 900nexus or a DJM 2000. Both mixers work, and all 3 CDJs should work, but this is what I use for a DJM 900nexus and 4 CDJ 2000.
Make sure they are all connected by PRO DJ LINK (including the mixer) via ethernet cables and at least a 5 output LAN switch. Have 6 - 7 outputs to connect one or two computers with Rekordbox.
1) Turn on the fader start on all 5 units (use the utilities menu on the mixer).
2) Set Channel 1 and 2 to side A of the crossfader, and set Channels 3 and 4 to side B of the crossfader.
3) Set the crossfader curve to the hip-hop style (straight line on top) setting.
4) Take the audio outputs of track 1 and 4 and route them to a soundcard connected to Resolume (NOT the mixer).
5) Cue a song on players 2 and 3, and plug in a USB or CD with a longer (10-20 min, preferably .wav) SMPTE signal to players 1 and 4.
6) Adjust the pitch on the two SMPTE players to match the players 2 and 3.
Now when you bring the crossfader to either side (let's say side B for this case), the 2 tracks assigned to side A will be started at the same time, so the SMPTE signal will be perfectly in sync with the song.
Here's how you mix with it. You need to utilize the vertical faders if this is going to work. Say your current track is playing on side B (players 3 and 4). The vertical fader on channel 2 is all the way down and is cued to your headphones. Beatmatch in side A with the crossfader as close as you can. When moving the track back and forth with the jog wheels to match them, make sure you are doing so on the track that you are transitioning out of. This prevents the SMPTE signal on side A from going out of sync with its corresponding track. only slightly changing the previous visuals (which is ok, because after the transition side B will be replaced, and those visuals will be on their way out).
I also find that using this way to cue in a new track is more accurate than using the vertical fader with fader start, or the cue/play buttons. Or at least it's easier for me.
This way works well for me, because I use only vertical faders when I mix, so before I set this up my crossfader had no function to me.
If you are having trouble setting the player numbers on the CDJs (when it says auto in the utilities menu), unplug everything but the power and then go back to the menu. You should be able to change it now.