Can a shockwave movie communicate with a flash movie?


I think the question says it all… but I am going to teel you more about the problem.
I have a window containing a flash MX movie. A buttons in this movie opens a new browser window with a shockwave movie.
so far so good.

Now, the problem…
The shockwave movie is a game which, when finished should tell the flash movie to display a message saying ‘congratulations’.

Does anybody know how to achieve this??