How can you iterate / loop in a BPM if you can't use C# blocks

I can’t help with your exact issue. The best way I have learned is to first trace the steps you want to reproduce in the BPM. This isn’t exactly what you want, but some of it might help.

In my case I wanted to create a new line/release. So I opened the sales order entry form, navigated to my sales order. Then I started the tracer in Epicor. Go back to sales order form and create the new line/release. Go back to the tracer and stop the trace, and open the trace file.

I think you might want a method-directive. But not sure on the details. Change Op Description When Switching Resource Group IDs

For reviewing trace data I can’t recommend Jose’s trace utility enough!