Merging extra tags from two different folders

[Milind Joshi]

I have two folders with jpg files and sidecars created by digiKam. One 
of the jpg folders has extra tags. Is there any way to merge this tag 
information with the files in the other folder without disturbing the 
tag information in that folder? The filenames match with just a suffix 
added to the basename, e.g. xxx.jpg and xxx_suffix.jpg.