There is no nice solution for this, you will still need to disable some security part of CloudLinux like symlic owner protection.
If other users just need to read files I see a way to do it with:
1. Create vhost for that user, with document root like /var/www/test/ . With this a test vhost will be able to write/read files into it.
2. Mount that directory to each user with /etc/cagefs/cagefs.mp , just add /var/www/test/ in it and run 'cagefsctl --rmeount-all'.
http://docs.cloudlinux.com/index.html?mount_points.html
3. Create a symbolic link inside every virtualhost like:
ln -s /var/www/test /home/user/public_html/shared_content
This have to be done automatically with some cPanel hooks.