How do you segregate Customer Facing documents more than one page?

 How do you segregate Customer Facing documents more than one page?

I have a requirement from the business to have Invoices and Dunning Letters to print separately since the "stuffer" machine cannot detect multiple sheets needing going to the address on the first page.

I am sure Oracle has something out of the box. 

My research leads me all over the place.  These are XML based docs going from AR and Collections using XML Publisher. 

I look in Microsoft Word where I can view our template and see something called Paper Source, close but not quite.

XML Publisher leads me to Style Sheets which I think we are using but that led me to