Put the two radio buttons and the associated link into a separate form. Replace the link with a submit button (or submit image if you want it to look like a link). So you will have two forms both posting to the same controller action. Give your submit button a name
which can be used inside the action to determine which button was clicked. You could also use a hidden field. The first thing to do in the action is to determine which button was clicked and then read the appropriate request values for the radio buttons.
Another alternative is to have everything in the same form with two submit buttons and different names.