There is no shortcut to this while the document is in this pseudo label format. My guess is that the PDF conversion didn't convert to a table but to a dreadful mish-mash of text boxes or frames to retain the original formatting. You need to get that document into a table and then that table into Excel where you can use Excel tools to manipulate the data and remove duplicates, then mail merge back to labels.
Don't think of this as a label issue. Think of it as a data extraction issue.
If you want to send me a single page (change the names to preserve anonimity of the people involved) and I will see what is possible. In the meantime take a look at
http://www.gmayor.com/convert_labels...mail_merge.htm
Send it as a mail attachment to supportATgmayor.com (change AT to @) and put your forum username in the subject or it will be discarded.