I know that we can specify if a process is a Unit Process or a System Process on OpenLCA and I know how to do it. However I don't how to create a "sub process" that would be under a System Process. To better explain my self here is an image of what I want to do.
Processes A and B would be two "sub" Unit Processes and Process C would be a System Process. Then Process C could be used in a Product System without having to see its underlying Unit Processes, just the inputs and the ouputs.
If someone could help me out, I would be very grateful.