How to copy page from one document to another and include background

[taherte]

I'm trying to combine some of my Publisher documents into other similar documents to reduce the number of files I have on my system. I know how to copy a page from one document to another using Ctrl + A (select all) > Ctrl + Shift + G (or Home tab, Arrange group and Group) > Ctrl C or Copy. However, this method doesn't copy the background and in some cases I don't know where I originally got it (I've taken steps to remedy that problem going forward). How can I copy a page to another document and include the background? If that's not possible, what is the easiest way to copy the background separately?