How to prevent access to the vCloud Director System Administrator Interface

The vCD web interface exposes different functionalities on the same base url:

https://vcd.example.com/cloud - web access to the system admin

https://vcd.example.com/cloud/org/<orgid> - web access to the organization admin

https://vcd.example.com/api - api access

I wish to expose to my clients the organization admin interface and the API but prevent access to the system administration interface.

I have a loadbalancer in front of the vCD cells so I can do some filtering but I whould much rather be able to designate roles to the vCD cells and have dedicated vCD cells which expose the system administration interface to my secured internal LAN and vCD cells exposed to the customers with just the API and org admin.

Is there any way to disable the system admin functionality on a cell ?

Thanks,

Cristian