How to bind a single select question to a roster with extra options

Hi I’d like to create a single select question based on a roster listing, but add extra options to the single select question.
For example I have a roster with names: Person 1, person 2
I want to create a single select question like:

Who is answering the following questions?

  • Person 1
  • Person 2
  • Another person

Where the “another person” option is static. Is this at all possible?

I worked around this issue by adding a clarifying question before. i.e.:

Are the questions being asked by a household member or another person?

  • Yes
  • No, by another person

If yes, who is answering the questions?

  • Person 1
  • Person 2