Custom status based on chosen payment gateway
Listen for the onBeforeOrderComplete event and do something like this (replacing values to match your setup).

craft()-&gt;on('commerce_orders.onBeforeOrderComplete', function($event){
    $order = $event-&gt;params['order'];
    if ($order-&gt;paymentMethodId == 2)
    {
        $order-&gt;orderStatusId = 3;
    }
});