Dropbox to OneDrive Large Folders

Hi all,
New to Hazel and have just got my first few rules up and running.
Essentially a big thing I want to use Hazel for is to copy any changes I make to documents in OneDrive(which has autosave and sharing functionality so I use it) to Dropbox which is my cloud storage of choice for a number of reasons.
Up to now I would just copy the One Drive Folder to Dropbox at the end of the day and hit merge on MacOS to update the changes. Hazel takes that task away which is great. So I have no problem setting up the rule on a per sub folder basis, to simple copy and replace when a file is modified in OneDrive.
However, will I need to create a rule for each subfolder? The large enclosing folder is exactly the same in both destinations but has about 40 subfolders, so I'd love to avoid making 40 rules. Now I know I could make the rule for the large folder that if anything in it changes to copy it, but that seems uneconomical because it will then replace the full folder in the destination and then reupload to the full folder to the cloud including 99% unmodified files.
What I would like is for Hazel to monitor the parent folder and if any file in any subfolder changes that this specific file is copied to the corresponding subfolder in the destination and therefore only the specific file is replaced.
Any thoughts or help?
New to Hazel and have just got my first few rules up and running.
Essentially a big thing I want to use Hazel for is to copy any changes I make to documents in OneDrive(which has autosave and sharing functionality so I use it) to Dropbox which is my cloud storage of choice for a number of reasons.
Up to now I would just copy the One Drive Folder to Dropbox at the end of the day and hit merge on MacOS to update the changes. Hazel takes that task away which is great. So I have no problem setting up the rule on a per sub folder basis, to simple copy and replace when a file is modified in OneDrive.
However, will I need to create a rule for each subfolder? The large enclosing folder is exactly the same in both destinations but has about 40 subfolders, so I'd love to avoid making 40 rules. Now I know I could make the rule for the large folder that if anything in it changes to copy it, but that seems uneconomical because it will then replace the full folder in the destination and then reupload to the full folder to the cloud including 99% unmodified files.
What I would like is for Hazel to monitor the parent folder and if any file in any subfolder changes that this specific file is copied to the corresponding subfolder in the destination and therefore only the specific file is replaced.
Any thoughts or help?