How do I have two form actions, depending on a certain condition?
What you need to do (to make things work robustly and simply) is to write a form handler (server-side code) that does some branching according to fields in the form data - as the FAQ says at http://www.htmlhelp.com/faq/html/forms.html#two-action
There is kind of solution using JavaScript. But it is not 100% reliable because you can't be sure that your visitors always have it turned on. For those who had turned JavaScript off the behaviour of your form submitting may be not the one you want.