Just as a matter of curiousity, are you using this with another DLink? I am curious if it works with other brands.
Also, I hate to sound ignorant, but what are these different Macs you are referring to? Does the primary router/ap have 3 different macs associated with it, or something? My Netgear Me102 just has one MAC, but maybe things get more complicated when you have a combo router/AP.