[support] Mail to forum?

I am trying replicate the functionality of yahoo or google groups. That is, the ability to allow people to have discussions via email that are also stored on the web as threaded discussions and are searchable. I've tried some combinations of modules but haven't come up with anything that does quite what I want.

I'd like this to work withing Organic Groups. I did activate Forum, and installs OG Forum and Subscription and Subscription OG so that group members should be able to receive email notice of posts to the Group's forum, but to reply they will have to return to the site.

I'm running 5.7 on this site.

Thanks for any help offered.