Unloading external swf using New unloadAndStop

So I was reading in to unloadAndStop a little bit and found out this is the exact thing I need when loading my external swf’s which have sound on them. I am new to AS3 so please bare with me. I believe I understand it when applying it to loading one single swf. But I have my site set up a little differently by using a universal button for my links. How could I apply “unloadAndStop” as a universal function to when any button is clicked the previously loaded swf unloads? I also had a question about fading the swf’s in and out. I’m pretty sure from what I can remember that I can add the fades right in to my AS3 below instead of having to add them to each of the external swfs right? any ideas on how to do this. Any help will be greatly appreciated.

var Xpos:Number = 35;
var Ypos:Number = 260;
var swf:MovieClip;
var loader:Loader = new Loader();

var defaultSWF:URLRequest = new URLRequest("swf's/Home.swf");

loader.x = Xpos;
loader.y = Ypos;

// Btns Universal function
function btnClick(event:MouseEvent):void {
    var newSWFRequest:URLRequest = new URLRequest("swf's/" + event.target.name + ".swf");
    loader.x = Xpos;
    loader.y = Ypos;
// Btn listeners
Home.addEventListener(MouseEvent.CLICK, btnClick);
About.addEventListener(MouseEvent.CLICK, btnClick);
Producers.addEventListener(MouseEvent.CLICK, btnClick);
Engineers.addEventListener(MouseEvent.CLICK, btnClick);
Pics.addEventListener(MouseEvent.CLICK, btnClick);
Movies.addEventListener(MouseEvent.CLICK, btnClick);
Contact.addEventListener(MouseEvent.CLICK, btnClick);