Assuming the templated emails come from one or more addresses that aren't also used for personal corporate email, then you could do the following:

 

1) Setup another server instance to act as a gateway. I have successfully used hMailServer [1] and emailrelay [2]. I prefer the latter although have only set it up on Linux. Make sure it is locked down so that it can't be used by unauthorized users. For example, configure it to bind only to localhost on a separate port such as "55555" and to send email out only on the configured interface.

 

2) Add the server created in step 1 to SmarterMail as an "Outgoing Gateway". Choose a priority other than "5" such as "1".

 

3) Add a "Sender Priority Override" for the email addresses that send templated email and set the priority to match the outgoing gateway created in step 2.

 

[1] https://www.hmailserver.com/

[2] http://emailrelay.sourceforge.net/