スタッフに加えてグループ特定のウィスパー

[Heliosurge (Dan DeMontmorency)]

This feature request might be of interest as an alternative

Flarum-bbcode-hide-content

Developing a plugin allows users to hide content from other users by using BBCode. Add the following BBCode to your post: [LOGIN]content to hide[/LOGIN] : hides the content from the non-logged in users [LIKE]content to hide[/LIKE] : hides the content until the user likes the post [REPLY]content to hide[/REPLY] : hides the content until the user replies to the post