X.org with multiple video cards

[Brian Fallik]

I asked this question on the gentoo forums and didn't get any response,
so I'm moving upstream.

I have an nforce2 motherboard (w/ built in video chip) in addition to a
nvidia GeForce4 Ti 4200. I currently have the nforce video disabled and
only use the 4200, which works perfectly in x-org 6.8. 

So here comes the question. 

1. Can I configure x.org (and the kernel, and udev, etc) to recognize
both video cards? 

2. Can I configure x.org to use the nforce2 as a secondary screen, as
though it were a dual head configuration?  I want both screens to be
controlled by a single terminal/login/session.

3. Can I have this controllable, so that it only happens occasionally?
In other words, the monitor I connect to the nforce2 may not always be
connected and I don't want any errors in this case. 

Thanks in advance!