XML Gallery Album categories

I have seen the XML Gallery tutorial and it looks great but how do you add a category or album list next to the imageholder? this way the user can select different albums and this list will be updated via the XML file…or do you have to create a new XML file called albums.xml???

my second question is…how do you write the code for Flash to look in the album.xml and then bounce back to show the pics? do you write one XML file and one piece of code to do the whole thing???