Implement Left and Right Navigation between Modal elements?

Issue Summary

Hello, I'm using modal frame api along with automodal and was wondering if there is a way to navigate between modals on page with left and right arrows. Similar to what something like fancybox does between elements with the same rel tag. Would this be something that is difficult to implement? I'm using modal frame api and automodal for a gallery and want to be able to navigate to sibling elements in the modal frame instead of having to exit the frame and click the next image or video. Any suggestions for implementing something like this would be awesome. Thanks!