Search by rating

I would like to use the extension Search&Filter combined to your plugin.
THere is code to add to each page, looking like:
<?php echo do_shortcode(‘[searchandfilter fields=”search,category,post_tag” types=”,checkbox,checkbox” hierarchical=”,1″ ]’); ?>

How can I add the “rating average” for the post onto the searchfilter?
The idea would be to be able to search only post with 4 stars for example.

It seems that no one asked for that so far, and I tried a few code, but none is working.

Thanks