Keeping Track of Sales Force and Commissions

I need a plugin or theme that will allow me to add sales forces and calculate their commission based on sales and sales tiers. Each sales force member could have teams of their own, so I would like to be able to drill down from the admin level down to the sales force teams. Each sales team should be able to see their team members and their sub-teams and so on.

Does anyone know of a plugin or theme that will do this?

Thanks!