Set up for Z4000 transformer and DCS

I have three connect o gauge loops and one simple standard gauge loop going around the perimeter of the layout. I want to be able to operate PS2 and conventional locomotives for both gauges. I can't figure out how to wire between the transformer and the TIU so I can operate the O gauge from one lever of the Z4000 and the standard gauge from the other one. I managed to set them up for the O gauge operating from the left side throttle but could not get the DCS to recognize the PS2 standard gauge loco using the right side throttle with the wiring going from the right side to the other fixed port on the TIU, which is how the left side is wired but with a jumper between the fixed and variable ports on the left side of the TIU. Am I wrong in thinking that The Z4000 is like having two transformers in one so that I can operate two separate loops form the same device and going from each side of the transformer to go to each side of the TIU's fixed and variable ports?