partner function to find head of the org based on the employee of the org

Hi,

I am looking for a way to populate a partner function on the order based on the rep

for a given org unit, i have assigned the manager as the head of the org unit

and his reps (anywhere from 1 to 10).

so when any of the rep creates an order, i have to auto populate the manager

in my org hierarchy there will be about 50 managers and 500 users

Thanks