Dynamic thumbnails loading 3 per line

Who knows how to get this kinda menu: http://www.tutorio.com/tutorial/simple-flash-xml-photogallery/1 to only display a certain number of items per line? (I’m referring to flash file down the page a little that says “Choose Thumbnail” on it. The source code for this flash file can be found on page 2 of this tutorial)

As you can see, it currently has 4 thumbnail images, and all 4 of them are displayed on 1 line. But what if I wanted to tell Flash to only put 3 per line (thus 3 on the first line and 1 on the second). This thumbnail image menu is dynamically loading data from XML, so if I wanted to add more images to the XML file, I wouldn’t want these extra images added to the same line as they would run off the page! I need them to load under the existing ones… It can be done, I just don’t know how. If you know a tutorial on the web that does this, please post the link.

Cheers!