Run scans on a specific subnet

I would like to set up an Inventory scan that runs only on subnets I specify. The reason for doing this rather than a complete active directory scan is I have sensitive machines on separate subnets that I do not want to scan, but are still in AD. I am new at using PDQ Inventory, but after reading some of the documentation I think I need to create a New Collection. When creating one, I would like to just insert the /24 subnet range and let the collection be whatever machines are online at the time of the scan. I also can't assign specific IPs for every machine since they have DHCP not a static IP. Is there a way to do this? Thanks.