is there a text mode code to make a typeahead field only serve up members of a certain role?

In our custom form for adding Resources we want to be able to select a Content Strategist. The Typeahead field currently allows me to enter anyone from our firm regardless of their role. Is there a Filter that I can add that will just make only the Content Strategists be the possible roles to choose from? Obviously, we would then apply this to other fields for other roles we want to choose from. So if there is a code solution, how can I adapt it? Thanks!