Is there any way to prevent one client from scanning the other client's IP address? Or prevent them from pinging each other locally?
I have noticed that scanning the IP range from any PC brings up all IP addresses in use.
I am afraid there isn't really a way to block client-to-client pings. The reason being that the clients connect to each other directly, without their traffic reaching the Bandwidth Manager.
For example, you have computers A and B, and the Bandwidth Manager installed between the Internet router and the rest of the network. BM can control data flowing from and to the Internet, but computer A can talk to computer B directly and the Bandwidth Manager will not be aware of that.
Some network equipment (i.e. switches) permits blocking communications between clients, so you can check the specifications and user manuals of your network hardware and see if it can do that.