Electronic transaction data sets are processed for a multitude of disparate transactions using a plurality of autonomous payment networks. A software-programmed computer circuit receives and processes electronic transaction data to identify a buyer using information provided in the transaction data, and uses the identification to access buyer profile information for selecting one of a plurality of networks. In this context, a buyer can be identified using one of a plurality of identification approaches (e.g., different account IDs), and such identification can be used for retrieving and using electronic profile data to select a payment network for the buyer, which may be completely independent from the identification. Payment data is accordingly configured so that the selected network can receive and process the data, such as by configuring the data into a network-specific format and/or communicating the data using network-specific protocols. The configured payment data is transmitted to the selected payment network, for use in effecting electronic payment for the transaction.