Assign Promaster per Location / Process Group

Provide Promaster permissions but limited to specific site/location, meaning a process group folder. For example, we have 4 locations (Turkey, Spain, China, US) and I would like that the promaster permissions are limited to the site folder (process group of USA) to approve processes, archive them, etc. In this way, we avoid the risk that a promaster from other location reject one of my processes, when they shouldn't touch them, since are not in their location.