Wild card modal email forwarding to rails application

Hi
May be a long story. Sorry for that.My requirement as this. I have a
saas application. The different people can create accounts. Each account
holder can create users under them . An example is during account
creation one user gives email as "[email protected]’. Then after login
to application he creates say two users and gives (valid) emails as
[email protected] and [email protected].

At a later stage from the application he send mail to both the above
users and they get mail in there gmail and yahoo inboxes. Also what is
sent to them etc are stored to db also as a thread. Upto this everything
works fine.

So coming to my requirement suppose [email protected] replies to this
email. Then [email protected] gets email in his inbox(This also can be
done). And also it has to be reached to my rails application . Dont know
how to do this???.And also to be logged to my db.

The above is the original requirement. As part of that what I would

like to know is can I reply mail to [email protected] (An
example is [email protected]) . The thing is [email protected]
is not a valid email. Like that there may be [email protected]
,[email protected] All these are dynamically created when replying.
And what I need is, all these mails has to be reached at
mydomain.com and forwarded to my rails application. From there I can get
the thread_id from this mail (example 100 from [email protected])
and also the mail contents so that everything like subject,body etc can
be stored to my db.

Dont know I could make you understand my requirement. Please tell if
you did not understand. Guide me with your valuable comments

Thanks