Ask for help! - users' own messages for DND in Polycom 301

Hi, I am new here.
We use Polycom 301 or Polycom 500. There is a key in the phones
"Do Not Disturb".
I already set up asterisk server. And each users can have their own
messages. Now I am asked to implement such a function that each
users can have 2 their own messages-----one plays when they are
unavailable or busy, and one plays when they press "Do Not Disturb"

I really don’t know whether it is possible to implement it. If when we press
"Do Not Disturb", the phone set the busy signle. And I don’t know whether
it is busy or “Do Not Disturb” is on.

Thank you so much!!!

He, is it possible? Any suggestions I appreciate