Hi Deb,
If you are using the full Enterprise Suite, you may be able to use a component/module to join the PDFs, but I am not sure.
If you are using LC Designer to create the forms, then no, you wont be able to join them using script. The only way I know of "joining" them is to open both in Designer and manually copy the contents of one form into new pages in the other form.
Niall