HTC Aria :: Way To Program My Phone For Area Code Recognition

Is there some way to program my phone so it knows my local area code? Reason I ask is that I never entered area codes for many the contacts on my old phone, which are all on my SIM card, because I could enter my area code into memory.I just got my Aria, and when I get a call from a contact within my area code, their contact name, which is saved on the SIM card, does not come up. Instead, their entire number, with area code comes up. Do I need to go in and input the area code for all of my contacts that have the same area code as me???