How to Set Minimum Order per Customer Group

in ,  
Just tryed this new version (prestashop 1.4.7.0) and I have more problems with this one on a 1.4.5.3 version, with this cart-summary.js file the total amount of the cart is not updated on onepage checkout when you modifiy quantity.

 How to set minimumPurchase amount for a group in Presta 1.4.7.0:

if (self::$cookie->id_customer)
{
$customer = new Customer((int)(self::$cookie->id_customer));
if ($customer->isMemberOfGroup(???))
$minimalPurchase = ???;
}

replace ??? with your variables!