Acting as Proxy Manager - security to exclude HR from seeing HR

Summary

We need to secure the Acting as Proxy Manager functionality so that HR Advisors can not see anyone within HR Departments

Content

Our Org Structure has our VP of HR reporting to an SVP who supports both HR and also Supply Management.  We need to prevent HR Advisors from seeing other HR employees when they Proxy as a Manager.  I am able to setup exclusion rules to exclude all HR departments and anyone under the VPs position (including his position) for person security for the HR Advisor custom role.  However, when they Proxy as a Manager and search the SVP (who has both HR employees and Supply Management employees reporting up to him), the HR Advisor can see all HR employees.