HI Heraleen
Is there a reason you can't point you GRC [GDV] system to your ERP DEV system to import the roles since that is your source of truth? If it's for BRM, I would have thought you want the DEV client as that's where you maintain roles in the first place before transporting through the landscape?
If testing the User Access Processes, you just need to pick a test ERP system to connect for the scenario. The roles and users are really the data. You would run the object sync for the Test ERP system to import the role exists flag for BRM so provisioning can occur.