List 2 fields in drop down list

I want to be able to have 2 fields to appear in my drop down list. I have a WWID field, and a Name field. I want the user to see both the WWID and Name in the drop down list, linked by the WWID. Since there are over 200,000 people in my company, Names are common, so it can be distinguish by the WWID. The user may or may not know the WWID when entering the data. That's why I want both field to show. How can i do this? Can someone help?