On a single entry page I'm displaying that entry's ratings using {exp:rating:entries}. Within each rating returned, I'd like to display the average of some/all of the different ratings fields for that rating.

So I need something like {overall_avg} but it's an average of the fields in that single rating rather then an average of all ratings for that entry.

I don't see any combination of tags that can make this happen. Any creative ways to achieve this?