But then to ensure that that 'right' unknown person is at the meeting you basically have to invite the whole company. Much better to send out a quick "hey, anybody done any work with Monte Carlo simulations before" on the company mailing list.
Maybe twice a year you can have a big 'all-hands' all day work shop where you go through and discuss major long term issues.
I was thinking more about the case of "here's how we are doing it" and someone you wouldn't have thought to ask saying "oh, we tried to do that at [x] last year and it didn't work because [a], [b], [c]".