Load and play different external MP3

Question

I wanted to do something I thought was simple - I wanted to have a sound playing (loaded external mp3) and then have various buttons on the screen that load an alternate song in its place.  Could someone please help me?
This is what I'm trying to do:
var myMusic:Sound = new Sound();
var reqMyMusic:URLRequest = new URLRequest("mySong.mp3");
myMusic.load(reqMyMusic);
myMusic.play();
music1_btn.addEventListener(MouseEvent.CLICK, music1);
music2_btn.addEventListener(MouseEvent.CLICK, music2);
function music1(event:Event)
    // LOAD AND PLAY A DIFFERENT MP3 (in place of mySong.mp3)
function  music2(event:Event)
    // LOAD AND PLAY A DIFFERENT MP3 (in place of mySong.mp3)

Answer 1

use:
var myMusic:Sound = new Sound();
var reqMyMusic:URLRequest = new URLRequest("mySong.mp3");
myMusic.load(reqMyMusic);
var sc:SoundChannel = myMusic.play();
music1_btn.addEventListener(MouseEvent.CLICK, music1);
music2_btn.addEventListener(MouseEvent.CLICK, music2);
function music1(event:Event)
sc.stop();
myMusic = null;
myMusic=newSound();
myMusic.load(new URLRequest("whatever"));
sc=myMusic.play();
function  music2(event:Event)
sc.stop();
myMusic = null;
myMusic=newSound();
myMusic.load(new URLRequest("whatever"));
sc=myMusic.play();