A method of selectively actuating well tools includes the steps of: selecting a well tool for actuation by current flow in one direction through a set of conductors; and selecting another well tool for actuation by opposite current flow through the set of conductors. A system includes multiple control devices that control which well tool is selected for actuation in response to current flow in at least one conductor set. A current direction in the conductors selects a certain well tool for actuation. A method of using n conductors to selectively actuate n*(n−1) well tools includes the steps of: arranging the conductors into n*(n−1)/2 sets; connecting the conductor sets to respective groups of the well tools; and controlling direction of current flow through at least one of the sets of conductors, thereby selecting at least one well tool in the respective group of the well tools for actuation.