ActionScript 2.0 :: Creating A Simple Back Button?

I have made a flash site that contains a lot of buttons that loads imported swfs. Now, I want to create a simple back button by using variables.

An example: The visitor clicks on the contact button which loads the contact.swf Then, the visitor clicks on the About us button which loads the aboutus.swf. Now, the visitor wants to go back to to the contact page and hit the back button inside the About us page.

The code for loading the pages looks like this:

on (release) {
_root.section = "nameofthepage.swf";
_root.transition.gotoAndPlay("closing");
}

Now I want this to happen: When the visitor clicks on the contact button a variable is saved named "contact" and then inserts "contact" in the code of the back button. Something like this:

on (release) {
_root.section = "insert the name of the current variable name.swf";
_root.transition.gotoAndPlay("closing");
}