how to contact the landing light to 3 switches; one at the bottom of the stairs, one at the top of the stairs and the third onw will be further down the upstairs landing. I have wired 2 way lights and I assume the the third switch (which is the further down the upstairs landing) will be the same as the one on the top of the stairs, ie the common the the common and the L1 to L1 and L2 to L2. Am I right and thinking this way.