Merging metadata

[ebr]

I have used MM to create all my metadata (because I was using it before discovering MB) and I actually kindof like its metadata utility but it is missing a couple of key bits needed by MB like MPAARating and IMDBRating. I'd kindof like to keep the MM info though because it contains other good bits like aspect ratio (very important for us CIH guys) and media type (DVD, BD, etc).

Is there any easy way to merge some of this info? Some sort of utility that would add the rating tags to my existing mymovies.xml files...?