Path to shared files depends on the user

Can anyone help?

I’ve recently migrated data to a new NextCloud server.
This data now belongs to user A.
I’ve created a group to share this data with, that group includes User B and User C.

Now, i’ve got InDesign files with broken internal links.
The paths, that used to be MacintoshHD:Volumes:PROJECTS, are no longer valid, which is normal.
To fix this, User B accesses the file and restores the link. The path shows as:
However, when user C accesses the file, the link is still broken, as on user C’s side, the link shoud probably be userC:PROJECTS

My question is : apart from creating a shared user, is there any way to use the initial absolute path for the files?

It looks like NextCloud is making a “copy” of the shared files in my users’ folders, instead of my users accessing the files directly.

I think this is similar to this topic but there has been no answer.

Am I missing something ?

(I’ve tried the documentation but I could not find anything.)