Toggling a layer's visibility

THanks for the reply. I recall having read that in a post made several months ago. I guess I'm not sure how to handle the task at hand then. In the previous thread(s) I had read, it was recomended to convert the layer into a movie object and toggle it's visibility. I'm still getting a handle on the flash object model and I can't say that I've got a firm grasp just yet. I've got a very simple flash movie with our County map as the very base layer and then for the first 25 frames I've got an image showing specific locations (exported as an image from a GIS). THen from frames 26-50 I've got the previous layer visible and an additional layer turns on with more locations identified. I was hoping to give the user the ability to toggle any of the layers on and off on the click event of a couple buttons I have.

I'm also wondering if I've got the movie set up in the most effecient manner? I've got a next button that goes from 1-25 on the first click and then from 26-50 on the second and then 51-75 etc.... In terms of a movie playing though, there's really no animation.