A method is suitable for processing a plurality of electronic documents designated for processing and delivery to a plurality of recipients, each recipient having a zip code associated therewith. Each electronic document is assigned a plurality of attributes, and the documents are sorted into one or more attribute groups based on the attributes, such that the electronic documents of each attribute group share at least one of the attributes. Output groups are then formed from the electronic documents of each attribute group based on the zip code associated with each electronic document, such that the electronic documents of each output group have similar zip codes. The output groups can then be routed to processing sites for processing the electronic documents to form physical documents for delivery to the recipients.