[Dovecot] remove mails from shared folders

[Patrick Fischer]

Hallo dovecot
This is  my first post on this list.

I'm new to IMAP servers and i read lots of howtos.
If I use the wrong term for some features please tell me the right term.

I have installed dovecot under ubuntu 7.10 and it works fine.
dovecot + fetchmail + postfix

I would like to use shared folders the way that we have an email pool 
for info at mydomain.com

user1 at mydomain.com -> User1
user2 at mydomain.com -> User2
user3 at mydomain.com -> User3
info at mydomain.com -> Pool
(look at this http://decembersoul.dyndns.org/wiki/images/c/c6/IMAP1.jpeg )

The users can see and process emails from the email pool. To process an 
email the user move the email from the email pool to his own inbox. This 
should make sure that only one user process a email.

Shared folders are created by symlink.

The problem is that, if a user move an email out of the email pool, the 
other users still can see the mail in the pool.
It takes a long time to remove the mail from the pool for every user. 
Move TO the pool works immediatley.
The user can make a "compress folder" to remove the emails but this 
can't be the soulution.

Maybe this is a client failed (tested only with thunderbird)

Best regards
Patrick Fischer