Full Organizational View from Top-Down

I am getting a continual request from top-level managers to see all of the employees they are responsible in the Web Portal. Right now, they can only see their direct-reports which is based on who they are a Manger of in AD. They cannot see the direct-reports of their Managers., Has anyone ran into this scenario and know how to resolve it? I believe delegation can resolve it, but I can't see how the delegation can automatically apply to new employees or a change in organizational structure.

Thanks for any hints or point in the right direction!