Answered Getting the Current Resource's Resource Groups

$rgrs = $resource->getMany('ResourceGroupResources');

foreach ($rgrs as $rgr) {
    $groupId = $rgr->get('document_group');
    $group = $modx->getObject('modResourceGroup', $groupId);
    $groupName = $group->get('name');
}

<?php


$returnString = "";


$rgrs = $modx->resource->getMany('ResourceGroupResources');


foreach ($rgrs as $rgr) {
    $groupId = $rgr->get('document_group');
    $group = $modx->getObject('modResourceGroup', $groupId);
	
	if($group)
	{
		$groupName = $group->get('name');
		
		if($groupName != "")
		{
			if($returnString == "")
				$returnString = $groupName;
			else
				$returnString = $returnString . '...............' . $groupName; 
		}
	}
}


return $returnString;