mail system in java

In my webapp i have some users, thats are in 3 Roles. i want to do communication
between them via mail system. this means that Role 1 attach one file and this
file must send via mail system to Role 2 (Role 2 mut can see in his page,
attachment file and username that send this attachment file) and also Role 2
after doing some works, send this attachment or new attachment file to users
in
Role 3 and ....(My server is tomcat) i read the apache mail system in http://
commons.apache.org/email but it seems that can send mail with attachment to
specified mail address, and it isnot compelte mail system for receiving
attachment from users.
have you any idea?
thanks very much.