By default, the following groups are created automatically. You cannot delete these groups.
You also cannot create a group with the same name mentioned below.

A group indicating all users of cybozu.cn.

A group indicating cybozu.cn Administrators.
cybozu.cn Administrators

This group can be used only by the system.

It is a group shown as Logged-in user on the screen.
It can be used to configure access permissions, filters, and notifications.

Users can use Logged-in user when they want to filter the data made by themselves.