How to program line key for incoming number on spa508g

I am utilizing the 8 buttons so 4 of them are BLF, 2 are extension buttons, such as extension 1000, and I would like to make the other 2 buttons show when a specific number is dialed. For example, they have offices in 3 states and I would like to know when a call comes in for an arizona number and another button for a New Mexico number.

So if the Arizona number is dialed, how can I show this on a button so they know they need to answer that call with an Arizona greeting and then a different button for the New Mexico incoming number?