Filter IP ranges on Azure Sentinel search

Hello everyone,

I'm using the query described https://github.com/Azure/Azure-Sentinel/blob/master/Hunting%20Queries/SigninLogs/UserLoginIPAddressTeleportation.yaml to get alerts on suspicious logins from different countries, but I get lots of false positives from people connecting to our VPNs.

Is there a way to filter using IP ranges instead of specific IPs? I've tried using this

let excludeKnownVPN = dynamic(['127.0.0.1', '0.0.0.0', '123.231.0.0/16']);

but I don't get the expected outcome (I still get alerts from those IPs).

If someones knows how to filter IP ranges out, I'll greatly appreciate it.

Best regards!