Why does my caller ID show the same name for all contacts?

[AC Question]

Problem:caller ID shows the same name for all contacts

Hi,

I have programed multiple office coworkers contacts that have the same phone number but with different extension number. The problem is that the when they call the caller ID show only one name. The name of the person that I first use with the corporate number. The syntax that I use is 1-898-830-9426, 2002 or 1-898-830-9426, 2003 so on so on. How can I make the caller ID to show the name of the contact based not only on the phone number but also the extension number?

thanks.