Ask about Flow Rules

I want to create a rule like the following, only devices with IP addresses and (i.e. Local Server and Public Server) can communicate with each other over the ZeroTier network. While other devices cannot communicate with each other, unless the devices want to communicate with the Local Server. What is the code for the rule?
I tried to use the rule I created, but it’s wrong

ip && not (ip.src == && ip.dst == ! && ip.dst == !

please help me, i’m new here :slight_smile: