The answer is yes -- it's possible. But the default template does not do it. You would need to customize the deployment manager artifacts we use to deploy these clusters. If you want to do this, send me an email and I'll get you connected with a copy of those templates that you can adjust to your needs.
The number of zones and number of core nodes are different considerations. What I meant was that if you want to do this "zone spreading" it would be good to have as many zones as you had nodes. So for example, if you have 3 core nodes, you'd want a minimum of 3 zones. If you put 3 nodes in 2 zones, then still you could lose your cluster if one zone went offline, and the point of doing this is to maintain HA if a zone drops out.
Different regions have different numbers of zones, so depending on how big your cluster is and your HA needs, taking this approach you'd want to choose your region carefully to maximize this spreading.
https://cloud.google.com/compute/docs/regions-zones/
Also note that google names the zones differently per region. It's for these reasons that we didn't build this into the google template by default. In our AWS templates, we limit deploys to only those regions with >= 3 AZs, and then we round-robin all nodes across the AZs.
