Buddypress email messaging system

I'm looking for some ways to allow users to answer or send group messages by email.

I can't find anything: anyone has some suggestion?

To clarify, what this plugin must do is something like a mailing list (e.g. what Google Groups does) that allows subscribers to create new posts or at least answer existing ones by email, not just through the website.

The theoretical logic would be something like that:

- subscribers receive an email message from a website email address (eg discussioni@domain.tld)
- subject (or the header) would contains discussion related IDs, in order to allow the plugin to know where the reply comes from
- user can reply, keeping the subject intact
- the plugin read the inbos (POP3 or IMAP) and from the subject/header it will understand where to place the answer

I'm quite new to BP, but as far as I can see this can't be done yet.

If this doesn't exists (or can't be done), there is anything I could use to replace Google Groups (so, free, less "old technology", and fully integrated with the email)?