Refer Information To Form

Hi, I am trying to link to a form from several places around a website. Each link corresponds to a different topic in a dropdown field on a form page. I would like to either be able to have the drop down field default to the correct topic based on which page it was referred from, or pass/add information to the link, so that when they click on it, the form's page url is different and will trigger the drop down to change.

Is this possible with a macro?