LOOKING FOR A MOVIE TITLE

I am looking for a movie title. Unfortunately I can only remember plot, please
help.

The movie is from ethier Australia or New Zealand, and was made during the
1980's. The movie plot revolves around a rural schoolhouse which is taken over
by a group of gunmen. A female teacher and her small group of students are
taken hostage and forced to walk a great distance by these gunmen. I only
remember couple of scenes. There is a scene where the female teacher and her
students are forced to swim quite far underwater through a cavern/grotto, while
holding their breath. One student panics and almost drowns along with the
female teacher. The end of the movie has the female teacher and some of the
students killing the gunmen or at least the ringleader as I seem to recall.

I have searched a lot of Internet movie databases to no avail. Does anyone
happen
to know the title of this movie?. Any help would be greatly appreciated.

Thanks,
Nicole

<<The movie is from ethier Australia or New Zealand, and was made during the
1980's. The movie plot revolves around a rural schoolhouse which is taken over
by a group of gunmen. A female teacher and her small group of students are
taken hostage and forced to walk a great distance by these gunmen.>>

The film is "Picnic at Hanging Rock".


Gene Stavis, School of Visual Arts - NYC