Selectively load different playlist using one XML?

Hello.

I am not sure if this is possible or not but I hope to find the answer here.

I have a page with a Flash MP3 player that uses an XML file to load a playlist.
I would like to make the player work in a way that depending on what variable is attached to the URL, the MP3 player will load a different playlist, all the while using only one XML. So for instance:

XML would be like this:
<title pagename=“a”>
<song>song1.mp3</song>
<song>song2.mp3</song>
</title>
<title pagename=“b”>
<song>song3.mp3</song>
<song>song4.mp3</song>
</title>

If the page is loaded as “http://www.whatever.com/mp3player.html?pagename=a” then it will load song1 & song2.

If the page is loaded as “http://www.whatever.com/mp3player.html?pagename=b” then it would load song3 & song4.

Is this possible to do and if so how can I achieve this?
Thanks in advance!