Routing traffic from Internet to BIG-IP VE in GCP (Google Cloud) - 3 NIC

I have deployed the active-passive pair in GCP with three nics. https://github.com/F5Networks/f5-google-gdm-templates/tree/master/supported/standalone/3nic/existing-stack/byol

Eth0 for external front-end application traffic (virtual server) ,

Eth1 for MGMT,

Eth2 for Back-end application

I have configured a CIDR range of 32 address spaces on Eth0 of one of the F5's to have some range for Virtual servers. The problem is - how in the world do I route traffic to any of the Virtual Servers with IPs in that range? These are GCP internal addresses, The Internet knows nothing about them. The only way traffic can get to the F5s is using the External IP of the Eth0, but how do I route that to the specific Virtual Servers? I hope I am missing something simple here.....

In a non-GCP equivalent this problem does not exist, because ISP/DNS provider can route traffic destined for Virtual Servers, since they have external IP addresses, whereas in GCP, the Virtual Servers are limited to using the Internal GCP CIDR-range limited range.

Thanks in advance,

-Vitaly