Using querystrings, GET, or LoadVars

I have a flash holdaycard on a server with its html file. I want different signatures to load from and xml or text file into the swf depending on what link a user clicks on. Is there anyway to use a querystring at the end of the url to tell flash which xml file to load?
I want to have one html file, one swf and a bunch of xml files on the server so embeding anyting into the html file wont work i dont think.