You can use the file /etc/synthetic.conf to map your old folder to a new virtual folder on the root directory.
If the file doesn't exists, just create it with sudo :
sudo nano /etc/synthetic.conf
Add the folder you want to use in the root directory, and the directory you want to mount on.
my-cool-directory /Users/Shared/Relocated Items/Security/my-cool-directory
Finish by rebooting your mac.
PS: Be careful with your synthetic.conf file. A colleague emailed the content of his file and it had a space between the virtual name and the path. Your system will simply power-off about 15 seconds into the boot process.
You must have only one tab character only between
You can find more infos with