1. A system by which a provider bank performs lockbox processing for a plurality of customers of a client bank, the system comprising: a central delivery point for receiving lockbox receipts on behalf of the plurality of customers of the client bank; a provider bank environment established within the provider bank, the provider bank environment comprising: a lockbox processing system, the lockbox processing system receiving the lockbox receipts from the central delivery point and generating credits with respect to the lockbox receipts, a provider bank environment processor coupled to the lockbox processing system, the provider bank environment processor receiving the credits from the lockbox processing system; and a client bank environment established within the provider bank, the client bank environment comprising: a plurality of customer accounts corresponding to the plurality of customers of the client bank, and a client bank environment processor coupled to the plurality of customer accounts, coupled to the client bank, and coupled to the provider bank environment processor, the client bank environment processor receiving the credits from the provider bank environment processor and applying the credits to corresponding ones of the plurality of customer accounts, whereby the client bank can offer lockbox processing services to the plurality of customers without having any lockbox processing capability within the client bank.