Multi staircase, how to wire a dual control switch

10 years, MS no one answer? This is actually simple, if there are only four floors, then the second and third floors installed two dual-control switches, one of the second floor and the first floor to form a dual-control, one with the third floor to form a dual-control, the third floor of a dual-control with the second floor to form a dual-control, a dual-control with the fourth floor to form a dual-control, one and the four floors only one dual-control double switch!