Hi @LauraGarcia0784,

I couldn't find a way to assign a discussion to teachers specifically, but as the members you want to participate are all teachers, you could create a discussion board and leave it unpublished. It will still function as normal and allow you to respond to each other; it just wouldn't be visible to students. (Which I'm sure is preferred with your use case!) Alternatively, you can ask an admin at your institution to create an account-level group.

I hope this helps!