Hi,
VZGPO was used in former times, in newer releases it's table VDGPO.
There should be at least one record per contract in VDGPO, the link is field SOBJEKT.
VDGPO contains the partner relationship, so it is typcially updated with contract change (FNVM).
BUt it could also happen in other transactions like borrower change in FN8X.
Kind regards,
Michael