How to create a bus

I have a Allen & Heath MixWizard3 16:2. We have two female vocalists in our group who needs compression on their channels. The problem is that I can't add compression to the channel inserts because they don't want to be compressed in the monitors. I need to compress their vocals in the mains only.



I know this can be done but I'm stump. Any suggestions?

How to create a bus