How to reject high scoring spam?


I have set up Mail-in-a-Box for the first time.
It works fine, but I have a question.
I would like to reject high scoring spam messages without putting them in the spam folder.
Is there any way to do this?
For example, I want to reject emails with an “X-Spam-Score” of 15 or higher.
I’m using Mail-in-a-Box 60.1.

Best regards.