2 ZT networks; How 1 device can talk to another on different ZT networks?

Greetings!

I appreciate your energy and activity on the boards. Thank you for responding. Ironically, lol, I found you replying to another thread that was relevant AFTER I made my post (Connect between 2 ZT networks)

I then started to think about just putting on the same network and use rules since I’ve seen some references, however I couldn’t lock it down as I wanted.

I only want device X to communicate with device Y on a certain port. Still trying to figure it out without breaking my network. I either locked it down completely where other devices could not communicate with device Y (on the certain port that device X only can communicate with, I forgot to test if any other port).