class Objednavka extends Nette\Object
{
    public function setDelivery($delivery)
    {
        $this->values['delivery'] = $delivery;
    }

    public function setInvoiceAddress($address)
    {
        $this->values = $address + $this->values;
    }

    // ...
}


public function ObjednavkaSubmitted($form)
{
    $obj = new Objednavka; // nebo nacist z db;
    $obj->setDelivery($form['delivery']->value);
    $obj->setInvoiceAddress($form['invoice_address']->values);
    // ...
}