dovecot - Jan 2014 - dict ldap

Hello everybody,

Dovecot 2.2.6 with LDAP auth against AD (Samba4).

I would like to know if it's possible to specify an LDAP transport for 
dict (something like dovecot-dict-ldap.conf.ext).
I'm in need to setup shared mailboxes and if I could query LDAP, that 
would help a lot.
IE : user1 user2 user3 are in OU=group1, so group1 (setup as user in AD) 
would share its mailbox with user1 user2 and user3.

Thanks in advance for your time.
Nicolas