I have installed hylafax on Ubuntu Server 8.04 with an external USRobotics modem.
Everything is going fine.
I use it almost as a fax2mail gateway.
The fax is behind a PBX.
The fax server receive every fax destinated to the internal fax N.1 (internal number 201)

I would like to make what follows:
I have other internal fax machines connected to the PBX.
Fax n.2 for sales department (internal number 202)
Fax n.3 for technical department (internal number 203)

Using the PBX control panel I can route all incoming fax for Fax n.2 and n.3 directly to Fax n.1
So I could use those fax machines as "out-only" machines.
Faxes originally intended for Fax N.1 should be mailed to "info@intranet.com"
Faxes originally intended for Fax N.2 should be mailed to "sales@intranet.com"
Faxes originally intended for Fax N.3 should be mailed to "technical@intranet.com"

The problem is that I don't know how to tell hylafax that a particular fax was originally assigned to Fax n.1, n.2 or n.3.

I can't do that checking "callerID" because there are customers that can send us faxes regarding one departement or another.
I can't do that using multiple modems cause i have not enough ports. Moreover I would like to use other fax machines. Up to 7 fax machine at the moment.
There is a way to tell to Hylafax that a fax was initially intended for fax n.1, 2 or 3?

Can anyone help me?

Thank you in advance.