code: public boolean isGroupContainer(CmsObject cms) throws CmsException {
  
          if (m_resource == null) {
              initResource(cms);
          }
          return CmsResourceTypeXmlContainerPage.GROUP_CONTAINER_TYPE_NAME.equals(
              OpenCms.getResourceManager().getResourceType(m_resource).getTypeName());
      }
docs: Tests whether this element refers to a group container.<p>
  
  @param cms the CmsObject used for VFS operations
  
  @return <code>true</code> if the container element refers to a group container
  
  @throws CmsException if something goes wrong