Set custom ad for calls from specific numbers

Hello, as per the title I need to set a custom announcement that is only played for calls that come from specific numbers set by me. For all other calls instead I intend to keep the current announcement that I have already set unchanged. How can I do this? Thank you

If the number of caller ID numbers is small, you can do this in inbound routes. Create one new route for each CID number and go to the other announcement. How many CIDs do you need to manage in this way?