I’m afraid I’m having trouble visualizing your desired output here. It’s much easier to understand coding questions by looking at code, rather than reading a verbal description. I think you’ll be more likely to get helpers to take an interest in this question if you can make a small reproducible example demonstrating what you mean.
No need to include your actual data frames — small example data frames with a similar structure will probably be easier to understand. It would also be a big help if you can include an example of what the desired output should look like.