The following example checks that the logged user belongs to the admin group and accordingly allows CSV downloading of records. If the user is not a member of the admin group, CSV downloads are disabled.
On the hooks folder look for the tablename.php
function tablename_init(&$options, $memberInfo, &$args){ if($memberInfo['group']=='Admins'){ $options->AllowCSV=1; }else{ $options->AllowCSV=0; } return true;}