EZMLM -- Send to subset of list subscribers

Hello all:

I need to send a message to a given subset of list subscribres.

The list is set up to use PostgreSQL in the back, so it's possible to
know which adresses should receive the intended message, right there
in the DB.

Short of hacking the code directly, Is there an easy way of telling
ezmlm to select just the emails that I need, and deliver the messages
just to those?

Any pointers would be greatly appreciated

Rubén.