Excuse for a delay with answer – I had 2 weeks vacation.

This is a feature active at User Role Editor by default.
Any user with ID not equal 1 (WordPress default admin user) which has ‘edit_users’ capability does not see users with ‘administrator’ role.
Pay attention that if user has ‘ure_manage_options’ capability URE counts him as a superadmin and does not apply to him any restrictions.

Another way to restrict what users are shown (available for editing/deletion) to the current user is Other roles access add-on.