Block the creation of a public subnet/interface in PowerVS workspaces at Enterprise Level or IAM

Banco Itau wants to hide/block the creation of the public subnet and/or powervs vm public interface. 

There must be a way to block this creation at Enterprise level or an IAM action specific for PowerVS public interface. In VPC environment we have floating IP and public gateways to reach internet, but they can be blocked. In PowerVS the public access is handled different and it is seem by Itau as a security concern