Problem: HR/MedRecords in disjoint RDBs


Imagine a database table in one company:

FredCo Human resources record
idnamemanagerhealthProviderhealthPlanId
1Pat2DRDs21852779q3
2JeanNULLDRDs21738239q3

and a database table in a completely separate institution:

DRD (health care provider) record
idnameprimaryPhysfoots-the-bill
s21852779q3Pat186FredCo
s21738239q3Jean718FredCo