General Public Emails (acknowledgements/remarketing)

Hello! We are learning as we go with our first-ever exhibit. We are selling walk-ups as general public sales, and have decided the best thing to do to capture emails and sent order acks is with the Alt Address in the order header. 

Is there an out-of-the-box way to pull a list of these general public emails for remarketing? I don't see much in the documentation but I could be missing something. I don't think lists/output sets offer much help here(?). Would love the community's feedback!