How to stop sending keys and mouse broadcasts to a client ?

Hey,
I'm pretty ure it has been discussed already, but don't know what to search for, so: what's the easiest way to stop sending keys and mouse broadcasts to a client ? Eg: You have a setup with 5 clients, but you only want 4 of them to follow broadcasts, while 1 of them should just stay there idle.

Thanks in advance for answers

[MiRai]

This is how you do it for your Repeater, but the concept is similar for any Mapped Key in ISBoxer:

http://isboxer.com/wiki/HOWTO:Broadcast ... of_windows

Thanks for the quick answer