how to do a multi-stage content upload

Hi all,

I am trying to make a classified module. I need to control the actual node submission process redirecting to a second form based on what is filled out in the first. I can't seem to find the right hooks in drupal to do this. I see the hook for outputing a content form and for handling the form input, however I don't see any hooks for handling page/form flow. Does anyone have any ideas on how I could do this?

thanks in advance,
Christopher Hamersley