Maybe someone need this edit
in /controllers/front/OrderController.php
edit around 67 line from:
$orderTotal = $this->context->cart->getOrderTotal();
$minimal_purchase = Tools::convertPrice((float)Configuration::get('PS_PURCHASE_MINIMUM'), $currency);
to
$orderTotal = $this->context->cart->getOrderTotal();
$minimal_purchase = Tools::convertPrice((float)Configuration::get('PS_PURCHASE_MINIMUM'), $currency);
//Edit by VuCumBra
$customer = new Customer((int)(self::$cookie->id_customer));
$groupes = $customer->getGroups();
if ($groupes[0]==3)
{
$minimal_purchase=300;
}
Just change the id group
if ($groupes[0]==3)
and the minimim amount
$minimal_purchase=300;
Hope this help