forms -- which pah?

hi guys and gals, I have a problem with my form which has left me scratching my head. Up the top of my form I have my <FORM ACTION="scenario1.php" METHOD=GET>, but the problem is that the conditions that are/are not met during the execution of the form depends on which file will be fetched. For example, just say I have two different categories through my form, category A and category B. If Category B is > 0 (this value can only be derived through the execution of the form) then scenario2.php is the page I want to proceed, but if category B = 0 then scenario1.php should execute. If I have an if statement up the top of the page it does not take into account the values assigned to category B because the check has been made before the form has been executed. If I put this before my submit button at the end of the form, once everything is executed, then I lose all my details from above this if statement. Has anyone got any idea on how I can do this? Thanks In Advance. Michael Webmaster, Real General Manager Inc. http://www.realgm.com