This is exactly what I was looking for, did not realize this was a method as I was instead looking at the private position property. Thank you!

See my reply to Ben, below. Unfortunately it seems the first process is not necessarily correct for instances with an upgrade history from Caché to IRIS.

Thank you for asking this, Ben. The superserver is not the first process and comes after auxiliary write daemons. I also found multiple cases for instances that upgraded from Caché to IRIS where the first process uses cacheusr but the superserver uses irisusr. So this will not work. I think we may be stuck with looking for the superserver process.