Category select list for search instead of text input

Is it possible to have a select list input for the search, rather than a text input? I would want the select list to only include the categories we have available.

For instance in our demo that’s under construction we have 2 categories Attorneys and Financial Advisors. Rather than having an “open” search input I would like a select list input where only Attorneys and Financial Advisors are the only choices. See attached image of what we’re after and here’s the website under construction:

http://simplereciprocity.com/

I don’t mind hard coding this into the plugin if need be as we will only have a few categories and I can always make adjustments as plugin updates are released.