code: public function getContentElementGroup($element)
  	{
  		foreach ($GLOBALS['TL_CTE'] as $k=>$v)
  		{
  			foreach (array_keys($v) as $kk)
  			{
  				if ($kk == $element)
  				{
  					return $k;
  				}
  			}
  		}
  
  		return null;
  	}
docs: Return the group of a content element
  
  @param string $element
  
  @return string