PDF Template Xpath Expressions

I am trying to populate a T5 and need to reference an element that is outside of the repeating group. I have tried to use Xpath but have not had success. I cannot change the XML layout. Are xpath expressions allowed? If not is there an easy way to re-format the XML. I tried using the BI Publisher Enterprise Data Model but the documentation says that "There is no metadata available from XML file data sets, therefore grouping and linking are not supported".