A neurostimulation system and method of providing therapy to a patient implanted with a plurality of electrodes using a plurality of electrical sources is provided. A source-electrode coupling configuration is determined from the electrical sources and electrodes. Electrical current is respectively conveyed between active ones of the plurality of electrical sources and active subsets of the plurality of electrodes in accordance with the determined source-electrode coupling configuration. The total number of the electrodes in the active electrode subsets is greater than the total number of the active electrical sources.