Global Approver Hierarchy

Hi All - we are currently doing an implementation for a global company starting with wave 1 in Italy. For this wave only 1 LE and 1 BU are being set up. Their requirement is a global approval hierarchy for requisition and purchase order approvals. This includes users from several countries (US, Germany etc.) and LEs/BUs that will be set up in future waves. How do we set up these approver users to create a job role/supervisory hierarchy since they are not italy employees?

Is the best approach to create these users are contingent workers in italy and terminate their employment and rehire them in their LE when it is configured? Or is there another cleaner approach or best practice? Need this urgently TIA!