I don't think, that you can make sure that everyone receives the notification by an administrative setting. If your users do not look at the questions, this is more a cultural problem, that you want to try with software. And this usally does not work good.
In my opionon there are two ways to achieve what you want, but both includes your users.
* Every of your users can use the "Watch All" Function and will then be notified of new questions.
* Or you tell your users, that they should have a look at the questions regularly.