Assuming your form goes:
<form method="post" action="nextstep.php">
<select name="jobs">
<option value="1">UN Inspector</option>
<option value="2">Celebrity Stalker</option>
</select>
<input type="submit" value="NEXT">
</form>
In nextstep.php, the variable $job automatically contains 1 or 2 (or however many options you have)
if($jobs == 1) {
appropriate form here
}
if($jobs == 2) {
appropriate form here
}
Personally, I'd use includes, with the variables passed echoed where needs be. If includes aren't working, check php.ini in the paths section.
OR, you could use javascript to dynamically alter the form.target.value when an onChange event is triggered in the <select> statement.. so you have inspector.php, stalker.php etc
In any case, I urge you to have fun with your friend by slipping in fields like "Number of bowel movements per day" etc., and see if he spots em in time.
Or not.