Is it possible to restrict an Approver to certain permissions at the 'Parent' level in a hub set up?

Because Purchase Plus works off a hierarchy system, if the Approver is logged in at 'Parent' organisation level, the Approver has full Permission granted to view and action all Purchase Orders and Invoices from the organisations sitting below in the 'Child' organisations. These permissions cannot be restricted at the 'Parent' organisational level.

The Approvers are also able to match invoices from different organisations as long as the Supplier matches. We suggest matching Invoices for the 'Child' organisation under the 'Child' level, rather than the 'Parent' level, to avoid any errors.

Check out this article for more information, User Permissions.