Excluding HR employees from the HR Area of Responsibility

In our current security setup, Human Resource employees can see data for all employees in their Business Unit, including other HR staff. We need to adjust our roles so only specific HR employees can see their full Business Unit (including HR). All other HR employees should see employee data for their Business Unit, minus other HR employees.

How can we configure this? We do have a challenge where our HR people are not in one consistent department, so we are curious how others have set Human Resources up so that they do not fall within their own Area of Responsibility.