How do I set the CMS default home page

[Bobbo]

I know that I can set this in admincp, settings, options, content management.

Is there a way I could manilpulate this value via php/plugin?

Right now, unregistered visitors come to my site and they see a default section that has content for visitors specifically. However, once they register, they have permissions for additional sections. At this point, I would like their CMS default to be something different. This way, if they've got a cookie and go to the main URL of the site, they wont be forced to see the visitor section.

I've been unable to figure where in the vB process this data is pulled from the database and how it's referenced by variable, etc.

B