This is a variant of this question, reproduced below:
There are $n$ people, who will stand in a circle while a game master places a hat on each of their heads. The hats can each be one of $n$ colors (repeats allowed). Each player can see every hat except their own. They all must then simultaneously guess what color hat they are wearing. As long as at least one person guesses correctly, they win. If they are all wrong, they lose.
They may agree on a strategy beforehand, but may not communicate once the hats are placed. Devise a strategy which guarantees they win.
This is a classic problem. If you haven't heard of it, give it a shot before you move on!
Here is the twist:
To make things harder, the game master places a one-way glass between two of the people, Larry and Harry. This means that Larry can see $n-2$ hats (every one else's hat except Harry's), while all other players can see $n-1$ hats.
With this extra obstacle, can they still win (guarantee at least one person guesses correctly)?