RBAC for sharing networks within a group of tenants

RBAC for sharing networks across a group of networks needs to be added.
First it needs to be added to the network plugin to store the information on network document on all the tenant id's which can access the network.
See the spec.
https://specs.openstack.org/openstack/neutron-specs/specs/liberty/rbac-networks.html
You could create new rbac policy using
neutron rbac-create --type network --target-tenant <tenant_id> --action access_as_shared <network_id>
neutron rbac-list
neutron rbac-show <rbac_policy_id>
I found this url to be very useful for rbac commands. https://developer.rackspace.com/blog/A-First-Look-at-RBAC-in-the-Liberty-Release-of-Neutron/