A computer-implemented method for a trusted entity such as a Post Office to process bills from a plurality of billers includes generating aggregated listings of bills to be submitted each identified customer and making the aggregated listings available to each identified customer. The trusted entity may then receive orders to effectuate payment of selected ones of the bills in the aggregated listings from customers. The first trusted entity may request that a second trusted entity designated by each identified customer (such as a bank) guarantee availability of funds sufficient to cover payment of the bills selected for payment. A third trusted entity (a central bank) may then be instructed to carry out the payments specified in each of the received orders in batch mode by transferring the payments from the second trusted entities designated by the customers to respective fourth trusted entities (e.g., banks) designated by the billers.