Two claims, two sources, one visit.

A single ED visit often produces two separate claims — an institutional (facility) claim and a professional (physician) claim — and today those might arrive as a claims flat file from one system and a FHIR feed from another. This runs claims from both source shapes through the same chaining rules for deciding which claims belong to one emergency-department encounter: an exact same-day/same-facility match, a next-day transfer, a general date overlap at the same facility, or — since professional claims don't carry facility or discharge fields — a looser overlap-or-adjacent-day rule when either claim is professional.