In other words, I wouldn’t worry about how they’re connected and I would just write. You’re not going to be able to logic the connection between the RS and the OS in the same way that you can’t logic out the same connection in your “real” life.
Dramatica is specifically biased towards the MC and OS, that’s why the Crucial Element is a function of the MC and OS, NOT the IC or RS.
You could likely come up with a Premise statement that included the RS but that would require an entirely different model and one that would frankly be more about waves and colors and would be almost impossible to put into words.
The IC and the RS are along for the ride…just like they are in our own lives.