Q. Is there a way to query multiple networks in the Flows window?

A. No, you'll have to create a CIDR block that includes both subnets.

For example, if they are contigious, that's easy:

10.20.30.0/24
10.20.30.1/24


Can be grouped as:

10.20.30.0/23


If they are further apart, it might be harder to do that, or two separate searches must be used.