secure_access_group - really secure ?

[nservices]

Hi,
if am configure secure_access_group=access
(http://www.directadmin.com/features.php?id=961)
its set access permission on /home/username for Users, and /home/username/domains for Admins and Resellers

but, all config.php files backup from all users are located in /home/username/user_backups for Admins and Resellers without any security.

how i can secure backup directory for Admins and Resellers ?

Regards,
Nservices.