At work we have an older phone system where we dial the main phone number, then the extension after the phone answers. Calls from people at work show up on my T600 as aaa-eee-xxxx, where aaa-eee is our area code and exchange, and xxxx is unpredictable. Anyone know of a way to recognize these calls and assign a special ringtone to them? Right now they all produce the Unknown Caller Tone.