Possible? Replacing folders only, around the contents?

I have hundreds of folders, containing music. While the music would stay unchanged, i plan to replace only the folders, because i want to add or update descriptions to them. I know, how to copy only the folders, containing those new sets of metadata, then moving the files over, folder by folder. But maybe there is a way to "wrap" the new folders over the old contents, saving a lot of time?