It sounds like you grouped your crosstab on the first name only. I would recommend:
- Make a new Formula (Call it "FullName")
- In the formula, combine the first name and last name, e.g. something like {First Name}&{Last Name}
- Edit your crosstab to group by the FullName formula instead.
Does this help?
EDIT
Based on your comment, I don't think your comment is with Crystal. You need a "unique ID" of some sort, a distinct number for each person. My original suggestion was trying to use the user's full name as a unique ID, but that won't work if your dataset is big enough to include multiple people with the same name. Does your dataset have any kind of unique ID? What is this crosstab trying to display? There might be a better way.