For the product Doctor Fee assuming you are setting Expense Account as “Payable Doctor Fee”.
Have you considered having only one product as “Surgery by Dr. A” and set “Dr. A” as it’s Supplier. Also for this product set “Procurement Method” to “Make To Order”. This way When you sell the product, OpenERP will trigger a draft purchase order to buy the required quantities to the supplier thereby creating appropriate entries. The PO can then be confirmed separately.
This can be done when you are generating Sales Order directly through OpenERP and not “flown” through Bahmni as a part of order as it does not generate auto PO. (Quotation from ERP vs Quotation from Bahmni - Problem in Auto PO Generation)