I have the LG CU500 cell phone. It lists both my numbers saved on the handheld and sim card.Can I list just 1?

Is there anyway to just list in my contacts the numbers saved to my handheld, so that I can take advantage of individual ringtones, etc.? Right now it shows each number twice, once for the handheld and once for the sim card. I do not want to erase the sim card in case I have a problem with my phone.