Godox Rx/Tx to trigger remote on 2nd camera when firing 1st camera?

I have been trying to find a way to trigger my SL2 or 7D2 when I fire the shutter on my 5D4. I have a Godox X1T, X1R, and XPro. I just bought the X1R, and it appears I cannot use it to trigger the camera it is attached to unless I hit the test button on the X1T. I cannot believe that it is difficult to take an X-sync signal and fire a ground to the trigger port. The X1R will go back since I cannot do what I want, unless there is a way to use it even with some other product or a DIY pcb that I can put together.

Any ideas? Wouldn't it be an easy firmware update to the X1R to either allow both flash and shutter, just flash, or just shutter when it receives a fire signal from the X1T? It would be a very handy function for us sports shooters and would like increase the sales of the receivers if we could control an array of cameras as we take a shot on the master camera.

You're probably not aware of this thread:

Godox X1 system integration thread
https://photography-on-the.net …/showthread.php​?t=1455540

Okay, so since Godox doesn't do this, at least not with the R2 systems (presumably the Cells II older transmitters/receivers worked), so I returned the X1R, and instead picked up a YongNuo RF605 kit with cables for $33.

I just got these, set them as RF-602s, and this came with both Canon cables so I can control my Rebel or my 7D2 remotely. Works great, there is a slight delay as expected, it is about 1/5 sec or so. Something I will have to deal with during the games. That is the only downside.

Too bad, Godox could easily make the X1R serve one mode or the other so you could control a shutter or a flash at different locations from a master camera. It seems they used to have this. Yongnuo had this issue too, they had it with the RF-602, then lost it with the RF-603, and now the RF-605 (which is both an RF 603 and RF 602) can do this.