There are 6 ROLLING shelves on tracks, with space for 7. To access any one, you roll the others aside. There will be a light above each "bay", so all shelves and the "space" will have a light above it, and the "space will be illuminated. The two lights on either side of the "space" will illuminate the open space somewhat also. All lights are to be on at once. One end of the rolling shelves comes up against a wall, so a standard 3 way wall switch will be used. On the other end is where the 3 way pull switch is needed, A box at ceiling level would contain the switch, activated by chain and string. Boils down to needing a 3 way switch (SPDT) that is chain activated, mounted in a octagon box with adequate current ratings.