Pull up the phonebook, press the center menu button on any contact, then pick setup (second from the bottom). Change view from "All Contacts" to "Primary Contact". This will then change the list to show each name only once. Use right or left to change the phone number of who it will call between home, cell, etc. If that option is missing, the phones firmware is really old and would need to be updated to add that feature.

Yes, the software isn't as good as the Sony Ericsson phones I have owned in the past, but I have gotten used to it. I much prefer to have the Razr with better reception over my old T610 that I had to wander to parts of my house to use clearly.