This would involve editing the open.php circa line 35. To add code to check the department and add the proper location for the client to be sent to.
THIS IS UNTESTED
replace
$inc='thankyou.inc.php';
with something like:
if( $_POST == 'Sales') {
$inc='sales.inc.php';
else {
$inc='support.inc.php';
}
If you want to send them to another page (and not keep them on the support site and display a sales message or support message then I think that you would want to change line 33 - 35 and change the example lines above to be
if($_POST == 'Sales') {
<USERMENTION username="header">@header</USERMENTION>('Location: sales.domain.ext');
}
else {
<USERMENTION username="header">@header</USERMENTION>('Location: support.domain.ext');
}
Please note that these are examples, and are untested and might not work.