Thanks for your reply.
I suppose I need physical desktop sharing.
Essentially I have a virtual machine on Proxmox running Ubuntu 16.04 and instead of having NoMachine seeing only one display, I want to treat each of my client monitors individually, much like Windows does when using RDP.
Currently, when I access the Ubuntu Server with NoMachine and I maximize a window, the maximized window spans across both of my monitors instead of just maximizing onto one monitor. Thus, it is being treated as if I have one extremely wide monitor instead of two regular monitors 🙂