Change status code for "Host not found"

[Helmut Schneider]

Hi,

I'm running postfix as a relay connected via VPN. If the VPN is down
mails are rejected:

relay=none, delay=0.09, delays=0.06/0.02/0.01/0, dsn=5.4.4,
status=bounced (Host or domain name not found. Name service error for
name=EXCHANGE01 type=AAAA: Host not found)

Is there a way to change the dsn to 4xx and deliver it when the VPN is
up again?

Thank you!