Loan repayment for underserved area's?

I have been told there are programs for loan repayment for underserved or specifically designated area's. Been looking on the web and not seeing where this info is. Seems to me these programs I looked at are geared more tward physicians. Thru the grapevine, that in underserved area's you can get help onl loans. Wondering why this would apply to one facility and not others and so far have found no info.
thanks for any input.