Component rule on UNZ segment
The UNZ segment has a component rule that assures that the group of one interchange is not mixed up with the group of another interchange if a restart occurs.
The component rule is shown here:
InterchangeControlRef Element:$ = InterchangeControlRef Element:Partner Inbound UNB
Envelope Control EDIFACT Data
The rule states that the InterchangeControlRef Element of the UNZ must be equal to the InterchangeControlRef Element of the UNB. If an Inbound Partner Group is invalid and a restart occurs, the component rule keeps different interchanges from getting mixed up with one another.