AS3 dynamic call to MC - need help with Target Path

[luke_4_mls]

I'm working on the basics of building a Flash website. For navigation, I have several buttons in a MC (nav) that when clicked make the proper page visible and hide the current page. I've used clever naming to access the page MC's dynamically. Here's my code:

a1PAGE.visible = true;
b1PAGE.visible = false;
c1PAGE.visible = false;
d1PAGE.visible = false;
var current:MovieClip = a1PAGE;
 
nav.a1.addEventListener(MouseEvent.CLICK, BTNCLICK);
nav.b1.addEventListener(MouseEvent.CLICK, BTNCLICK);
nav.c1.addEventListener(MouseEvent.CLICK, BTNCLICK);
nav.d1.addEventListener(MouseEvent.CLICK, BTNCLICK);
 
function BTNCLICK(event:MouseEvent):void {
    current.visible = false;
    var caller:String = event.target.name + "PAGE";
    var called:MovieClip = this[caller];
    called.visible = true;
    current = called
}

It works fine. But I need to store all the pages into an MC. So here's that code:

pages.a1PAGE.visible = true;
pages.b1PAGE.visible = false;
pages.c1PAGE.visible = false;
pages.d1PAGE.visible = false;
var current:MovieClip = pages.a1PAGE;
 
nav.a1.addEventListener(MouseEvent.CLICK, BTNCLICK);
nav.b1.addEventListener(MouseEvent.CLICK, BTNCLICK);
nav.c1.addEventListener(MouseEvent.CLICK, BTNCLICK);
nav.d1.addEventListener(MouseEvent.CLICK, BTNCLICK);
 
function BTNCLICK(event:MouseEvent):void {
    current.visible = false;
    var caller:String = event.target.name + "PAGE";
    var called:MovieClip = this[caller];
    pages.called.visible = true;
    current = pages.called
}

Except Flash doesn't like my last 2 lines of code. (Error #1010: A term is undefined and has no properties.) So how do I reference the page instance name dynamically and add a target path to it that flash will accept? It must retain this structure:

Scene 1
|--AS located here
|--nav
| |--nav buttons
|--pages
| |--pages mc's

thanks for the help

[luke_4_mls]

I figure it:

pages.a1PAGE.visible = true;
pages.b1PAGE.visible = false;
pages.c1PAGE.visible = false;
pages.d1PAGE.visible = false;
var current:MovieClip = pages.a1PAGE;
 
nav.a1.addEventListener(MouseEvent.CLICK, BTNCLICK);
nav.b1.addEventListener(MouseEvent.CLICK, BTNCLICK);
nav.c1.addEventListener(MouseEvent.CLICK, BTNCLICK);
nav.d1.addEventListener(MouseEvent.CLICK, BTNCLICK);
 
function BTNCLICK(event:MouseEvent):void {
    current.visible = false;
    var caller:String = event.target.name + "PAGE";
    var called:MovieClip = this.pages[caller];
    called.visible = true;
    current = called;
}