Exception Rule for techmail-generated incidents

Summary:

We'd like to figure out how to create/adjust a business rule so that emails received that are responses to mailings can bypass our 'baseline' business rule which does not permit incidents submitted via techmail.

Content (required):

We have an incident rule in place that queries whether an incoming incident was created by techmail, and if so, sends an automated reply directing customers instead to our portal (we want them to engage with our knowlegebase), and then discards/does not create the incident.

However, we have some cases where we send a mass mailing through the Mailing function. Typically we want customers to respond to these (or at least be able to if they wish). When I added an additional IF statement to this rule of "Incidents Mailing ID is not null" (assuming that the mailing ID might be nested somewhere in the metatext), it did permit replies to come back. Unfortunately, it stopped suppressing ANY direct mail/techmail generated incidents, such that even if I sent an email to the service mailbox that was not in response to a mailing, incidents were being