Lets say you want to import dvd device from file 2 to file 1
You can make a copy of file2, open file2, delete all devices from main1/main2, except for DVD device. save this as a junk file 2

Importing into CCP is fairly simple. Just right click on Main. Import the junk file2 (you will see only the DVD device in the list. You can click on the left to select it). This way, there is less confusion about punch through or external device etc. (hopefully!).

You don't even need to make a copy. You can just import from file 2 and select the DVD device.