NPM Excluding network nodes from polling

Our network is a small to mid sized K-12 school district. I want to eliminate a bunch of the workstations from producing alert messages in NPM. All I want to see in the Solarwinds NPM alerts are our CISCO routers and switches and the Microsoft servers and virtual severs. I did not originally setup the NPM so I am not sure why we are polling all of the workstations but it doesn't seam helpful. In any case I want to filter them out of the alert messages. I am sure I am missing something very basic and just need to adjust a setting on my rules. So how do I remove these devices (the windows workstations) from reporting in solarwinds.  Can I totally remove them from NPM somehow or is there a way to shift them to a different view etc.; however, if I did I dont know enough about NPM to know exactly what the consequences of that might be so im still on the fence with that idea. I just seam to get a ton of polling information from nodes that hide more important alerts from our routers and switches.