I see 2 potential solutions... if man 2 and 3 are wearing the same color hat (say black), then man 1 knows he is wearing a white hat and shouts out first...
if man 2 and 3 are wearing diff color hats (one black and one white), then man 1 won't know what color he has, and won't shout...after a bit, if man 1 has not shouted, then man 2 will shout, as he will know the color of his hat, based on man 1's revelation (ie, if man 3 has a black hat on, then man 2 will know that he and man 3 have diff color hats, and hence can determine that man 1 and 3 have some color, and man2 is diff)...
does that make sense?