Custom layout of user data dirs

Support is available for customizing the data directory in a Nextcloud deployment. The data directory features a subdirectory for each user, and many other files and subdirectories for metadata. In the case of a pre-existing directory having a subdirectory for each user, is support available for Nextcloud using the existing directory for files, but not for metadata, for example, if the same data is used by other applications running locally on the server? Can the automatically-created user directories be substituted for symbolic links that point elsewhere on the system?