On Apache you could easily configure it through an htaccess file:
<IfModule mod_fcgid.c>
Action php-fcgi /fcgi-bin/phpcgi-starter-5.3
</IfModule>
<IfModule mod_fcgid.c>
Action php-fcgi /fcgi-bin/phpcgi-starter-5.4
</IfModule>
Is there something similar for Nginx + PHP-FPM?