[Dovecot] Different authentication for pop3 and imap

[sh1ny]

Is it possible to run different authentications for pop3 and imap ? What 
i need is to give access to some clients to pop3 only and to other to 
imap only. I'm using postgres as a backend. What i actually need is 2 
separate queries for userdb, one to select with "WHERE imap_access = 1" 
and the other one with "WHERE pop3_access = 1" ( that's just an example 
). I'm using 1.1.2 but i plan on upgrading to either 1.1.4 or 1.2.