Stumped with window sensors - wired and the Schlage RS100HC

I’m trying Schlage’s RS100HC zwave sensor, but instead of using the magnet I’m using the internal hardwired connectors in series with my existing security system’s hardwired sensors. I’m trying to accomplish something like this:

What I’m trying to do is use that sensor in series with the wired ones so ST can get open/close status for a particular zone (supervised) at the same time as the Vista panel. I don’t want to integrate the Vista panel and SmartThings yet via an API because I’d like the two systems to remain separate for security reasons for now. I also have no idea how to do that with the API for the EnvisaLink 3 :frowning:

I’ve partially got it working, but I’m stumped on why the Vista panel still shows a fault even though I’m getting open/close notifications in ST when I open any of the three windows in that series. I installed the Schlage’s sensor in series as the last sensor in the panel itself, and the resistor is at EOL. I read a post by @twack on what he did with his setup, but I’ve not seen anyone try anything similar.

Any ideas why the Schlage sensor is tripped but why the Vista isn’t?

Any help would be greatly appreciated!