How to get a value from a graph of a dashboard


I want your suggestion so as to cover my need for cross-filtering and perform drill-down capabilities. I have a site (lets say on Apache) from where I am calling specific Metabase Dashboards through their url. Everything up to here is fine and the site plays great. The problem is if I click on a graph of a dashboard (lets say customers) and I want this specific customer to drill-down. Into Metabase-environmet with query-builder queries you can click on a specific column and select ‘Distribution’ and get the proper graph. Because discussion on drill-down is huge and on the other hand I have ONLY custom made queries, I want to know, if clicking a graph from a dashboard that has been loaded with iframe on my site, I can get this specific value, somehow.
With this way I can add drill-down capabilities and permit to user to perform data-mining easily.
I use the latest version of Metabase (v0.30.4) with Postgres 10.4 and the external site is on Xampp 3.2.1.
Applause for to the Metabase Team for its incredible work.

A possible solution is that of Metabase to implement a method of ‘window.postMessage’ to send info to an external site.