Lead tracking with hidden fields Forms 2.0 (non-marketo landing pages) ?

If I create a form using javascript and add a hidden field, can we use the hidden field in Marketo for lead tracking and segmentation? We would like to be able to assign a visitor to a specific group in Marketo based on which form they filled out, these forms (4 in total) would all be coming from the same page (i.e. the same URL).

Of course, but you don't even need a hidden field on the form to do what you're describing. The Filled Out Form trigger can be constrained by both the URL and the form name to uniquely identify all combinations.