Hi John -
Right now, there is only one A layer, but all content on it will move in sync and you could put, for instance, outlined objects on one part of it and text on another. To get images with some transparency, use PNGs instead of JPGs. You can also put scrolling objects inside of a box on the A layer to get a scrolling layer inside of a scrolling layer using this tip: http://magplus.zendesk.com/entries/20867562-tips-tricks-scrolling-text-in-box
Let us know if that solves it. We'll also look at multiple layers down the road!