Systems, methods, and computer program products for processing an online transaction to purchase a set of products. In response to receiving a request to process a transaction to purchase the set of products, an On-Line Transaction Processing (OLTP) system retrieves data from a corresponding database record that defines the set of products being purchased. The database record may also define a seller, a supplier, and a merchant for each product. For each product having the seller as the merchant, the OLTP determines a form of payment to be used to pay the supplier of the product based on rules governing forms of payment retrieved from a payment rules database. When the forms of payment have been determined, the OLTP system may add data to the database record that identifies the form of payment used to pay the supplier for each product in the record.