is there a way that the people im hosting their domain, and/or subdomains that they can have access to their own control panel? So far all they can do, and I know that they can access is their site via FTP
You and your users are all part of the same group, so it defaults to allow them read access to your files. You could try disabling group read and execute privileges (chmod -R g-rx) on your directories and folders, but I’ve never tried that.
To give them their own Control Panel, use the Panel’s Billing feature to give them Account Privileges for their Domain.