"FIG. 10 further illustrates an example of order visibility to participants in a market, [0025]FIG. 11 illustrates order visibility in a further example for participants in a market, [0026]FIGS. 12A and 12B are a flow diagram illustrating a further technique for making orders available to selected participants, [0027]FIGS. 13A, 13B and 13C are a flow diagram illustrating the formation of groups by" . . . .