What I would do is:
Find out from the Sending system what structure they are sending
Then relay that to the Receiving system.
If there are any differences, make adaptations in the engine.
Of course, I would expect that to be done for every field in the entire message so that everyone knows what can be sent and what needs to be received.
In other words, a full integration specification.
Jim Kosloskey
email: jim.kosloskey@jim-kosloskey.com 30+ years Cloverleaf, 60 years IT – old fart.