OPML provides Slideshow Pro with links to multiple xml album feeds for your gallery2 website.
configure line 30 of ssp.php and upload both files (ssp.php and opml.php) to yoursite.com/yourgallery directory
provide Slideshow Pro with your new opml url:
You can provide a specific album id to generate a feed of its direct sub-albums
Click the image to the right for sample ->