I tried making a VSFTPD user with access to all of our clients' FTP folders. (the users are all chroot'ed to their home directories, where the public_html folders are).
What I did was create a new FTP user and created a client directory inside
/home/global_user/. Then I used the following command to mount the client's user directory into the global user directory, like this:
mount --bind /home/global_user/client_directory /home/client/
What happened next is that indeed the folder was mounted, but all the files in the original folder are gone! They don't appear in the new mount either.