This is more or less exactly what we did for the Colonial and State Records of North Carolina (http://docsouth.unc.edu/csr), with additional metadata records in MODS in the dmdSec.  It seemed to work well for representing all the information we had.

Hugh

On Nov 10, 2009, at 12:27 PM, Rick Beaubien wrote:

I need to state right off that I am no expert in TEI.  However, if I understand correctly what you are trying to do, I would recommend using the mets/structmap/div/fptr/area element.  The area element is specifically set up to allow you to point to specific areas within an integral, typically external content file.  In a case where the external content file is a structured text file, such as an xml file, the relevant attributes on the area element would be: 

FILEID -- reference the ID value of the <file> element within the METS document's fileSec that represents the integral TEI file.
BEGIN -- reference the ID value of the first relevant element in the external TEI content file
END -- reference the ID value of the last relevant element in the external TEI content file.  But note, that if all of the pertinent content is contained within a single element, you only need to include the BEGIN attribute.
BETYPE--set the value of this to "IDREF"

Hope this helps.

Rick Beaubien