How to unload variables in xml

1

I have navigation built in Flash and XML. There is movieclip on the stage called “menu”, and there is multiline dynamic text called “info_txt” with variable name " displayText".

There is also movieclip called “container” to load external file into.

This is the AS:

menuXml = new XML();
menuXml.ignoreWhite = true;
contenttext = this;
menuXml.onLoad = function() {
	menuSection = this.firstChild.childNodes;
	for (var i=0; i<menuSection.length; i++) {
		item = menu.attachMovie("itemClip", "itemClip" + i, i);
		item._x = 0;
		item._y = 20*i;
		item.itemLabel.text = menuSection*.attributes.name;
		item.text = menuSection*.attributes.text;
		item.myUrl = menuSection*.attributes.url;
		item.onRelease = function() {
			info_txt.text = "LOADING...";
			// load the text into this timeline:
			contenttext.loadVariables(this.text);
			//getURL(this.myUrl,"_blank");
		}
	}
}
menuXml.load("myMenu.xml");

And this is the mymenu.xml structure:

<?xml version="1.0"?>
<PORTFOLIO>
	<section 	name="ABOUT"
			text="content/text/description1.txt"
			url="http://www.kirupa.com/"
	 />
	<section 	name="DESERT"
			text="content/text/description1.txt"
			url="http://www.bndsolutions.com.au/" 
	/>
	<section 	name="BUSHFIRE" 
			text="content/text/description1.txt"
			url="http://www.studiowhiz.com/" 
	/>
	<section 	name="BIRDS & BUSH"
			text="content/text/description1.txt" 
			url="http://www.macromedia.com/" 
	/>
	<section 	name="LAST MILLENIUM"
			text="content/text/description1.txt" 
			url="http://www.flashforward2002.com/"
	 />
	<section 	name="LINKS"
			text="content/text/description2.html" 
			url="http://www.erain.com/" 
	/>
	<section 	name="CONTACT"
			text="content/text/description3.txt" 
			url="http://www.friendsofed.com/"
	 />
</PORTFOLIO>

My question:

I want only ABOUT, LINKS, and CONTACT buttons to load the variable display text. When, DESERT, BUSHFIRE, BIRDS, and LAST button is released it will unloadVariable and do things like load external file (jpg, swf, etc).

I have tried to change the xml structure but it doesn’t work. Can someone help me…pleaaaaaaaaase.