At present we don't have a way to limit who is able to access and participate in your question. We do plan to develop a way to limit participation to those who have been sent a special URL.
One option is to filter the results to show only people who live in a certain area.
You can also add a supplementary data question relating to whether they are from a specific place (ie a resident of a particular street).
In addition, when you promote the question you focus on the people of interest.
You'll find people who are not affected by the decision generally won't participate anyway.