Limit who can post on a topic

[JammyDodger]

It’s not quite what you want, but there’s the Restricted Replies plugin that comes pretty close:

@David

	Summary	Discourse Restricted Replies adds a per-category setting allowing staff to restrict replies on topics to the topic creator and members of specific groups.
	Repository Link	https://github.com/discourse/discourse-restricted-replies
	Install Guide	How to install plugins in Discourse