Allowing specific web users to see Template Variables on specific pages

<?php
/*
usage:
add the following snippet call to either your template or document
content where you want the tv to appear

[!show_specific_tvs?
&tvs=`forum_lock,super_admin,can_post,can_view,can_edit`
&groups=`Forum Admin,Forum Moderator`
!]

** note that &tvs=`` are the names of the tvs used on the
   create/edit tv screen, not the display names used on
   the document edit screen

*/
$tvs = isset($tvs) ? $tvs : '';
$groups = isset($groups) ? $groups : '';

$valid =FALSE;
$output ='';

// check and see if the current user
// is in one of the valid groups
if(isset($_SESSION['webUserGroupNames']) && $_SESSION['webUserGroupNames'] !=''){
    $xplod_groups = explode(',',$groups);
    foreach($_SESSION['webUserGroupNames'] as $key=>$value){
        if(in_array($value,$xplod_groups) && $valid !=TRUE){
            $valid =TRUE;
        }
    }

    // if user groups is ok, get the template variables
    if($valid ==TRUE){
        $tv_values =$modx->getTemplateVarOutput(
            explode(',',$tvs),
            $docid=$modx->documentObject['id'],
            $published=1);

        foreach($tv_values as $key1=>$value1){
            $output .=$value1;
            //$modx->setPlaceholder($key1,$value1);
        }
    }
    return $output;
}
?>