title: fancybox 3 selector for dynamically added elements and multiple gallery
body: <p>In the documentation of fancybox v.3 says "Sometimes you might need to bind fancybox to dynamically added elements. Use selector...". Everything is fine, but I need to disable the automatic grouping of galleries and customize multiple gallery selector.</p>
  
  <p>Default behavior:</p>
  
  <pre><code>$().fancybox({
      selector : '[data-fancybox]:visible'
  });
  </code></pre>
  
  <p>All visible links with data-fancybox will be merged into ONE gallery.
  I need to create different galleries according to the values of data-fancybox, like data-fancybox="gallery1", data-fancybox="gallery2", etc. At the same time, fancybox should continue to listen to dynamically added content.</p>
  
  <p>Can you help me, please?</p>