Need Help with a Movie title?

I saw this kickass movie once when I was a kid back in the early 80's and the name has somehow escaped me. I remember bits and pieces of it, so here goes nothing. There is this class of students ranging in age from first graders up to about Jr. High kids with a female teacher who are taken hostage by a group of men dressed up in masks. I think one of the bad guys might have been dressed up like Santa Claus or something. Anyway the teacher and her students escape into the woods and are chased by the masked baddies. There is one scene where the class has to swim through an underwater cave and the female teacher knocks herself out by banging her head forcing the older kids in the class to take control of the situation. By the end of the movie the kids have turned the table on the killers and have turned the hunters into the hunted. Well, that's pretty much all I remember as far as plot goes.

If anyone could help me out with a name it would be greatly appreciated. I'm trying to relive all the "great" scares I had when I was a kid to see if these movies were genuinely good or it was just my age. I guess when your young, guys dressed up in halloween costumes terrorizing kids can be pretty freakin scary. Thanks.

[KRUGERKID13]

I also need help with the name of this film.
I was just about to start a forum asking the name of this particular movie.

The film you are talking about is "Fortress," an australian 1986 made-for-tv movie. The star was Rachel Ward. This is a very cool movie. It was released on VHS and BETA, now oop. I wish it was available on DVD.