Bridge CS6 rating info

Hi there, using Bridge CS6 (OS X 10.8.4).

I have a large number of .cr2 files and, in order to have a smaller file size to preview, I batch processed them all to .jpg files, while keeping the original .cr2 files on an ext. disk.

The filenames of the .jpegs are the same as the .cr2s.

I previewed the .jpegs and made some ratings using Bridge. Can anyone tell me how I can transfer/copy this ratings info from the .jpegs over to their original .cr2 files, or do I have to duplicate the info by manually rating each of the cr2s?

Many thanks for any help!