You can now enable unique permissions on a per-message basis by middle-clicking on the message in the GUI.

By default, the permissions for each message are set to "None", which means that all of your players will see the related message.

When you middle-click to enable the permissions for a message, you'll see "announcer.ID" in the lore for each message. Now, only players or groups with that permission will see the message.

It is recommended to delete your StyleFile.yml in the /plugins/Announcer/ folder on your server so that you can see the new options.