Asign customer to Trade group if he insers company details

[Jurist]

Hello,

As in the title, is it possible to assign customer to a different than a default customer group when he registers? I know it could be easily done via cron script that would go through entire database and just change ID of the customer group, but how to do that during checkout?

If "company" field is filled during checkout he is assigned to "trade" group. Any idea how to do that?

Thanks

[Jurist]

In case anybody were interested and having similar issue, AuthController.php processSubmitAccount() function needs an override. 

after line 244:

                            if($is_company)
                            {
                            $customer->addGroups(array(4));
                            }
                            else
                            {
                            $customer->addGroups(array((int)Configuration::get('PS_CUSTOMER_GROUP')));
                            }

Group 4 is my "Trade" group ID.