Sorry…no, there isn’t a way; NDRs (Non-Delivery Receipt msgs) only get sent to the sender of a msg. There isn’t a configuration or setting to send a msg to a recipient native to exchange.
But if you are using a separate spam product there is defiantly a switch to do this.
The reason it is difficult to get this going is because developers see this as a weakness to allow a spammer to get to your user even if the message is blocked. The subject will still come through and we don’t want that now do we… Especially if it is pornographic or disturbing.