RHEV (3.5) - How can I add additional NICs to create a new network?

Hi,
I am running RHEV 3.5 in my lab with currently 4 hypervisors attached. The VMs are using the rhevm network. I added an extra NIC on each hypervisor but cannot configure those NICs because they are now managed my RHEV-M.
I cannot figure out how to test and configure those interfaces from within RHEV manager.
Any help is appreciated.