just based on the fragrance version of this...
the way we did it was to make a list of who's in, organize into a rough sort of geographic route,
and then there's the seed. Either the person starting it has at least quite a bit to start, or a couple of people send theirs on ahead to make a big seed and then later on they receive the box...
I also PM'd WRAdvisor this thread so hopefully he'll come back here soon and organize this...
example from fragrances -
http://www.styleforum.net/t/241685/the-3rd-styleforum-fragrance-sample-swap-box/0_60