How to use Zoomify tile source in openseadragon?

Question

I'm trying to figure out how to use tiles generated using Zoomify output from photoshop in an openseadragon project. I gather that I will need to use a custom tile source to do this but the folder structure and file naming convention used by Zoomify is rather puzzling, so I was wondering if anyone had done this before.

I need to configure the getTileUrl function in the custom tile source so that it determines zoom level, row and column for each tile. I have previously used tiles generated with deep zoom composer with no problem (and without the need for a custom tile source), but I'm now using images that are too large for that to be practical eg 15 - 25Gig.

the example in the openseadragon docs is

tileSources:   {
        height: 512*256,
        width:  512*256,
        tileSize: 256,
        minLevel: 8,
        getTileUrl: function( level, x, y ){
            return "http://s3.amazonaws.com/com.modestmaps.bluemarble/" +
                    (level-8) + "-r" + x + "-c" + y + ".jpg";
        }
    }

but the zoomify folder structure is: ouput_folder > TileGroup179 > 10-100-44.jpg 10-102-44.jpg TileGroup18 > 8-0-24.jpg 8-1-24.jpg 8-10-24.jpg ... TileGroup180 >

Any help on this would be most appreciated, thanks in advance.