Restrict replies to a certain group of users

I want to make a forum for students and consultants.

Students: can create topics, only reply to their OWN topic they’ve created

Consultants: can reply to any post, can create topics

is this possible? The whole value add of our forum would actually be that you can ONLY get help from consultants, similar to the Q&A board on

Permissions are at the category level. You want them at the topic level. Changing that will be very difficult.