Multiple trunks & inbound routes

I need a little help. I have installed FPBX with AsteriskNOW 2.0.2 on a box with a Digium AEX800 with 8 FXO ports.

The location has 2 POTS lines coming in, one goes to the card (“line 1”), one is held out for DSL/Fax service (“line 2”) and is not used for voice.

The two lines are NOT configured as a hunt group with the telco.

The user would like to have line 2 available for outgoing calls, in order to keep line 1 free in the event of an incoming call.

In short, I would like to add line 2 to the AEX800 card but configure it as a separate trunk, used by a separate outgoing route, but not by any incoming routes (incoming fax calls would still go to the fax machine.) The user could access that route by dialing an 8 instead of a 9, for example.

I am confident I can set up the route, but I need to know how to set up the separate trunk within FPBX. Do I assign a different group number to the port on the card and direct the trunk to use that group? If so, how? Please advise.