Customizable Dial-by-Name prompt

Would like the ability to record a prompt for the Dial-by-Name directory. Use case is this:

We are a non-profit who serves teachers. We have a fleet of field representatives assigned to field areas made up of school districts. If a teacher calls, they may not know their field rep's name. In those cases, we would like to give them the ability to search by school district name in the Dial-by-Name directory. So, we would set up a "user" for each school district and have the caller enter the first few letters of their school district's name. The school district user's line would simply forward to the field rep's extension. I put together a proof of concept, and this works swimmingly. However, the default prompt for the Dial-by-Name directory says to enter the first few letters of the Person's first or last name, which would cause confusion for the caller.