Reject re-invite from FAX machine that uses T38 signaling - with HMR

How would I be able to reject a re-invite with an HMR from a fax-machine that uses T38 signaling ?

I would like to reject the re-invite which would cause the call to get terminated (which is the end goal).

Initial idea is to match on the "m=image" line in the SDP of the re-invite.

Thoughts?

The SDP of the Re-invite from the fax-machine is as follows:

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m=image 19164 udptl t38

a=T38FaxVersion:0

a=T38MaxBitRate:14400

a=T38FaxRateManagement:transferredTCF

a=T38FaxMaxBuffer:262

a=T38FaxMaxDatagram:176

a=T38FaxUdpEC:t38UDPRedundancy

a=sendrecv

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