[Discussion] Pin a reply to the top in a discussion

Problem statement:

Right now we can sort discussion replies from new to old or vice-versa, but the sorting seems to default to post the newest reply first. I want students NOT to be able to see any answers before they post, so we use that setting; But AFTER they post and can see ALL of the responses, I want them to see my explanatory text which will pop up at the top of the discussion replies, before they go further in discussion. However, if the default is to show posts from newest to old, then my explanatory post just goes down to the bottom, and I don't think students see it.

Proposed solution:

Can Instructors have the ability to pin a response post to the top of the discussion replies, no matter which way the settings for replies default? I want my "explanatory" text and answers to pop up at the top of the discussion so that it's easy for students to find it.

User role(s):

admin,instructor,ta,designer,observer