OK...Think it works OK for now, although I think the display needs a bit of tweaking.
LJ Tribe toy is here
EDIT: The bit that actually displays stuff is a bit broken. If it displays, it displays everything in a big lump rather than spread out like the original test had. Need to work out how to get that working.
EDIT: Ah ha! I appear to have managed to make it work now and it produces very pretty looking masses of names. The nearer someone is to you on the mess, the more likely they are part of your "tribe". The colouring is just to show how far away that person is from you.