Create the VMs in the same zone, and configure static routes with IP addresses as next hops.

Create the VMs in different zones, and configure static routes with instance names as next hops.

Create an instance template and a managed instance group. Configure a single internal load balancer, and define a custom static route with the internal TCP/UDP load balancer as the next hop.

Create an instance template and a managed instance group. Configure two separate internal TCP/UDP load balancers for each protocol (TCP/UDP), and configure the client VMs to use the internal load balancers’ virtual IP addresses.