A plurality of billers are enrolled in a by-item bill payment program. An invoice is obtained from a given one of said billers, including multiple charges corresponding to at least one of goods and services purchased from the given one of said billers by a first payor. The invoice is modified, based at least in part on said enrolling step, to generate at least one modified invoice including multiple charges corresponding to at least one of goods and services purchased from the given one of said billers by said first payor, the multiple charges being handled under different payment terms. The at least one modified invoice is sent to said first payor; payment from said first payor is obtained; and the obtained payment is allocated. A specific exemplary software architecture for implementing the method is also disclosed.