I could try, I am not sure whether it's possible but I believe it's a good way to check it
I think it is possible - I know a medium who "sent" me a dream, I didn't even ask him for that, next day he asked me if I dreamt about this particular thing and I was shocked because I did dream about it indeed.
But could have been an unlikely coincidence.
If you don't find enough people, I figure we could try on our own, just the two of us ?