Voicemail default announcement


I have the following problem:
How can i disable the default voicemail announcement only for one extension?
I know the option in "general settings"
Do Not PlayCheck this to remove the default message
(“Please leave your message after the tone. When done, hang-up, or press the pound key.”)
This option set the global “s”.
I want for all extensions the default announcement but not for the office.
The office have a custom voicemail announcement.
How can i to this in freePBX?