Need help with Text Field Replication

I have a single page form (in a pdf) that contains several text fields. I have three copies of this pdf form where I have filled in the text fields with unique information. Now I would like to combine the three pdfs into a single, three-page pdf, However, I encountered a problem. When I combine the pdfs the text fields of form two and three assume the information of form one. In other words, when I combine the three pdfs I get a pdf with three forms with the exact same text information.
How do I accomplish my goal of combining the three pdfs without the text information changing?