So I have a problem, If you work at a large corporation you just might understand. When I come up with something I want to do, that is out of the norm, I frequently get a "talk to X or Y" recommendation.
That leads to talk to A or B recommendation, and on and on, sometimes multiple levels deep.
I had an epiphany today, MIND MAP, so now I center the mind map with the topic I'm looking into, then I map the name(s) of who told me to talk to someone, then map them, so eventually you get a nice map of who you've talked to (and I'll usually note a date, or whatnot), and who you haven't.
This has the added benefit that if you come across a similar situation, you *might* be able to get away with chasing down the individual at the end of the map, not at the beginning (unless that's taboo, and you're supposed to follow the chain, but come on, who does that? We just want to get stuff done).
Good luck.
Tyson