Redmine

Custom field with the ability to enter only unique data.

The task is as follows: I created a custom field "MAC address PC" and I want only a unique MAC address value to be entered in this field. To make it impossible to assign the same addresses to different devices. According to the same principle, create another field name PC: "sv-srv-vk-20-1" so that it is also unique and cannot be repeated. I've only been studying Redmine for a week. Maybe there is some kind of plugin or implementation instructions?