Keeping both files when moving them to a different folder?

When I'm moving files to a folder with another set of files named the same, it doesn't give me the "keep both"-option. However when I move the files one by one, I get this option.
Any tips on how I can move large amounts of files and still get the "keep both"-option?


Solution 1:

If you hold option, the skip button should turn to keep both at least in 10.8.2.