I have my own email address through my Opalstack-hosted domain and would like to automatically forward specific emails that I receive  a reading tool I use called Matter. The reading tool gives me a unique, user-specific email address to which I can forward content.
 
Of course, I don't want all my email to go to the reading tool, just newsletters, for example.
Can someone point me in the right direction for doing this? Thanks!
-- Robert