Using Nero to burn multiple dvds onto a single dvd

I am going to use dvd shrink to selectively grab chapters from multiple dvds. Each dvd will have its own folder on my hard drive.
Then I want to use Nero to merge these files together onto my dvd. The instructions state “drag and drop the files to the compilation window” But seeing that I have multiple folders each with the same filenames how would I do this ? Do I rename the filenames? any advice would be appreciated.thanks