Starting Multiple X sessions

I know that you can start multiple X sessions, and here's what i'd like to do...

I ran a s-video cable from the puter to the TV in the living room. And i configured XF86Config so that everything works. Start movie on computer and watch it on TV. All works and all is good in life....

Here's the kipper...

It shows my entire screen, of course. And i cannot start a movie for the kid to watch, and still use my computer at the same time....

Here's the question..

Is it possible to make startx use a config file other than XF86Config? Say one named "XF86TV" or whatever you wanna name it? So that i can start a x session using the XF86TV config file, start the movie, then start another X Session for myself to use that has the TV-out stuff taken out of the XF86Config, so my screen does not show up on the tv?

Did that make sense, or am i rambling now?

you don't have to use a separate config file, but it is possible.. (i forget how at the moment).. you could just add new entries for the monitor output and then make a new screen section in XF86Config that points to the other devices and such instead of the TV-out stuff.. then make sure that you start the second X session with the args needed to use the second set of screen settings...