Feature to insert external subtitle file in full blu-ray movies?

In my movies library, I have a lot of full blu-ray discs in stracture of BDMV folders (not ISO).

I know that in Streamers it works if I paste the subtitle file to the main BDMV folder and give it the name: index.srt.

But its not working that way in Kodi (if i remember well, it worked in the XBMC generation…).

Is there a possibility to develope this feature?