Programmatically retrieving all Resource Groups for current resource?

$c = $modx->newQuery('modResourceGroup');
$c->leftJoin('modResourceGroupResource','ResourceGroupResource','
    `ResourceGroupResource`.`document_group` = `modResourceGroup`.`id`
AND `ResourceGroupResource`.`document` = '.$resource->get('id'));
$count = $modx->getCount('modResourceGroup',$c);
$c->select('
    `modResourceGroup`.*,
    IF(ISNULL(`ResourceGroupResource`.`document`),0,1) AS access
');
$c->sortby($sort,$dir);
if ($isLimit) $c->limit($limit,$start);
$resourceGroups = $modx->getCollection('modResourceGroup',$c);

 //add resouce to resource group
//$resouceID - resouce ID
//$resourceGroupID - resource group ID

    $resourceGroupResource = $modx->newObject('modResourceGroupResource');
    $resourceGroupResource->set('document', $resouceID);
    $resourceGroupResource->set('document_group', $resourceGroupID);
    $resourceGroupResource->save();

$resource->joinGroup($group);

<?php
$id = $modx->resource->get('id');
$rgrs = $modx->getCollection('modResourceGroupResource', array('document'=>$id));

$groups = array();
foreach($rgrs as $rgr) {
    $groups[] = $rgr->get('document_group');
}

/* see if we got them */
$output = implode(',', $groups);
return $output;

$resource->leaveGroup($group);

$rgrouplist = $resource->getGroupsList();
$rgroups = array();

foreach ($rgroupslist['collection'] as $rgroup) {
    if ($resource->isMember($rgroup->get('name'))) {
        // do something
    }
}