[tretiy3]

you can use mailgun for that. it has an api and concepts of "routes". you will be able to intercept email from seller@seller_domain.com to buyer@your_domain.com, handle it in your app (mailgun will POST to your web app), and then send from seller@your_domain.com to buyer@buyer_domain.com. really transparent. you can tweak any part of the workflow. have all conversations and all stats in your app.

[whoshallsucceed]

Yes, I found out after a while. I ended up doing just that. Last thing to figure out is how to send the mail as is, meaning for now I pick the HMTL part and send it setting the content type. But this way lacks the Text version of the email.

I'll keep digging up.

Thanks for following up!