[kh99]

It can be done - it's done in admincp/usergroup.php, in the section that starts with

// ###################### Start insert / update #######################
if ($_POST['do'] == 'update')
{

That code uses the values submitted from the adminCP usergroup form so you'd have to adapt it. For instance, some of the values are expected to be in $vbulletin->GPC['usergroup'], so you can easily replace that with your own array.