I am trying to accomplish the same thing but I’m having trouble figuring out where to place the code for multiple galleries on the same page. Here is what I tried:
<strong>Single Image</strong>
[gallery link="file" "colorbox-1" columns="1"]
<strong>Multiple Images</strong>
[gallery link="file" "colorbox-2" columns="3"]
I also tried editing the the CSS Class input field in the main Posting panel but it would only save one class for each page.