@downey Thanks — I should've thought of that. Although it's telling that I didn't; I remember hearing about it and I think I looked at it but couldn't really get into it, and didn't know anyone else who did either.
Had a "shower thought" earlier about how there could be potential in using an approach based on degrees of separation but perhaps a bit more flexible than what's described there on the wikipedia page. It'd get complex quite quickly. But it could solve a *lot* of problems.