To represent only one share class of a multiple-share class portfolio, set your search criteria to Distinct Portfolios = Yes. The share class that is chosen is the one that has been around the longest (that is, the one with the earliest fund inception date).
Tip: The easiest way to do this is to open the Search dialog box, then under View column order, click Alphabetically. Then, click in the Field column and begin typing Distinct Portfolio - when it appears in the list of options, click it.