PHP / switch version with htaccess

Hi,

I have installed both php 5.6 and php 7.0

My php 5.6 is activated on all my server

I would like to know, how, with the help of htaccess, I can activate php7.0 but only in a folder and all its children's folder.

With other host provider such as OVH I was using a .ovhconfig file to make the switch ( inside a folder )

app.engine=php
app.engine.version=7.0
http.firewall=none
environment=production

I Also tried with my linode, in a .htaccess

AddHandler application/x-httpd-php70 .php

without any success

What would be the best solution ?

Thanks