Not directly. You need an audio mixer with busses that you can assign individual channels too

doesn't seem like there's a practical way to do that at all.

On an SX/SZ, you could keep a click track on one of the 4 channels, arm the cue, and route the headphone jack to a separate mixer and bus out for the monitors, but you'd then have to plug your headphones into the mixing board and you'd constantly hear the click track when trying to cue.

If the source of the click track was actually coming from a type of midi-device then it is possible to sync to another device's time clock. But if the click track is just recorded in analog then it is just an reference to follow and true midi sync will not be possible.
One solution would be to have the backing tracks already pre-recorded along with the click track. But then what would you actually be doing?

Why? The drummer basically is the click track, and for any moments without a drummer, they should be able to feel when the drums are about to kick back in anyway. This is what rehearsal is for. I played in a band as DJ for years and we never needed anything like that, even though I was sometimes triggering from an MPC. MIDI might have worked if we implemented it, but we just weren't rolling like that at the time.

Is there any other purpose besides "keeping everyone in time"? Just trying to understand what you guys want to accomplish because maybe there's a solution.

I sometimes fill in on stage as a DJ with a cover band. (mainly just doing a little scratching here and there and then mixing videos during the band breaks.) The way they currently have it set up is the backing tracks are a split stereo signal with the left side backing tracks only coming out the mains. And the right side has backing tracks with a click track coming out only in the drum monitor. Which helps the drummer keep perfect time with the pre-recorded backing tracks which consist of anything from synth-melodies to back up vocal harmonies, etc.

I've searched high and low for help on how to use a click track in Serato and couldn't find any decent solutions. So after a few days of trial and error, I managed to work it out myself.

Here's how you do it...

First, you need to get a click track in audio form (mp3, wav, etc). You can make and download one for free at www.metronomer.com

Drag your metronome file into one of the decks (I use Deck 4 and save the first 3 for tracks).

Next set the beat grid and create a 1 bar loop for your metronome.

You will need a mixer that can route the click track (Deck 4 in my case) out via a separate output so that you don't here it through front of house. I have an Allen & Heath Xone 43C and use the FX Send to route the click track out a small mixer. The drummer then plugs his headphones into that mixer. This works perfectly and also gives the drummer control over the click level.

So now you have the metronome locked to the beatgrid and routed out via a unique send to the drummer!

The last step is to set the beat grid on all the tracks you want to play in sync with the click track. This takes a bit to learn at first but once you've done a couple of tracks it's pretty easy. Learn the keyboard shortcuts!

Yes, it is possible to integrate a click track into a Serato DJ- ddj sx/sz. You can use the samples and set a tempo, and then receive the click into a channel and then sync to it. You could also use beat matching skills to keep the click track in time with the sample. It sounds like you may want to try using the ClickTester application, which can help you get the click track and sample in perfect sync. Hope this helps!

You can then sync the click track to the sample, either by using beat matching skills or by using a tool such as clicktester.net , which can help you get the click track and sample perfectly in time.