Alright, it took me a while to get it to work in jsfiddle, but here it is.
Alright, you set the “data-fancybox-group” to group the different galleries together. You can see how it works. I have thumb1 and thumb2.
When it comes to the class, make sure the are “fancy-thumbs” and add the “hidden” class for each on that you don’t want to see, leaving one to start the gallery.
Also, the JS is a bit different and I had to load another js and css in for the thumbnails.
See how it works?