Webstorm 2017.3.1 - ES5 & ES6 in the same project

Hi, All!

Is there a way to mark some files from a Project as ES5 while all the rest of the project is ES6? Or the opposite?

I have this scenario, but I could not find a way to configure it like that.

The only option I see is File > Settings > Languages & Frameworks > JavaScript and the combo JavaScript language version shows EMCAScript 5.1 and ECMAScript 6, so I can choose only one that is used for the shole project.

Any hint?

Thanks!