Way to Elasticsearch returns similar docs count by each doc returned on search

I have a Elasticsearch index with many docs where the content of this docs is frequently similar, 'cause each doc is an article from a website.

Currently we need to know how many docs are similar for each doc returned on our search. It's like more_like_this functionality, but on more_like_this i need to pass the doc_id to do the search. In case, we would need to do a more_like_this search for each doc returned on a search, and it's not "cool".

Anyone know another way to do this?