Yes, you can. Add a junior mod group. Give this group the permissions that you want to add. Then when you add a junior moderator to a forum, make sure that you give the correct permissions per forum.
It's not optimal, since you can only decide to give 'manage threads' permission or not. This includes all dangerous thread related actions, like merging and deleting but also minor actions like open, close, approve, unapprove, stick, unstick and move.
I will post a modification request for this:
'manage threads' permissions for (junior) moderators