Do you know the "real names" as a whole, or are you trying to determine what the "real name" is depending on user ID? The easiest way is create a sub-table with 3 fields: USER_ID, LNAME, FNAME.
Then use the table as a matrix to display whichever name you wish to see. You can also concatenate the LNAME and FNAME if you want them to appear in a single cell on return.