Sharepoint 2010 Custom Search Result

I searched for this question,but have been unable to find an answer. Should be pretty straightforward.

I am attempting to edit the People Search Core Results web part for a team site so that the results page automatically includes all people reporting to a particular manager. I know that you use Results Query Options, and then Append Text to Query, but I have no idea what to enter in the Append Text to Query box to get the results I am looking for.

Does anyone know what to enter to only return results for people reporting to a certain manager?

Thanks in advance, Andrew