1. A method for processing an order based on inputs from an ordering user, comprising the steps of: creating a default-mechanism object, representing a mechanism to process a requirement of the order necessary to complete ordering and delivering of the order for a portion of the order not otherwise accounted for; creating an order-related structure for an order from the user, including: creating a plurality of order-related objects based on a plurality of order-related inputs obtained from the user, the plurality of order-related objects including an ordered-items object representing one or more units of one or more items ordered by the user; and one or more alternative-mechanism objects representing different alternative mechanisms to process the requirement of the order necessary to complete ordering and delivering of the one or more units of one or more items; establishing one or more specific relationships, wherein each specific relationship relates the ordered-items object and one of the one or more alternative-mechanism objects, wherein each specific relationship indicates that the requirement of a portion of the one or more units will be processed by the alternative mechanism represented by the corresponding alternative-mechanism object of the one or more alternative-mechanism objects, and wherein each portion is determined by a property of the corresponding specific relationship as defined based on said plurality of order-related inputs from the user, independent of the ordered-items object or the one or more alternative-mechanism objects; establishing a default relationship between the ordered-items object and the default-mechanism object, wherein the default relationship indicates that the requirement of a remainder portion of the one or more units will be processed by the mechanism represented by the default-mechanism object, the remainder portion comprising any part of the one or more items not included in a portion corresponding to one of the one or more specific relationships; and processing the order based on the order-related structure and the default relationship, by identifying for each specific relationship the corresponding portion of the one or more units to be processed by the alternative mechanism represented by the corresponding alternative-mechanism object of the one or more alternative-mechanism objects, and by identifying the remainder portion of the one or more units to be processed by the mechanism represented by the default-mechanism object.