yes you can, however you cannot get more than one ip address.
here is my setup.
ont -> cisco switch (public vlan) -> fortigate firewall -> cisco switch private vlan -> fios router -> tv's
off my fortigate and switch are the rest of my machines, I only use my fios router to handle the conversion between coax, and ethernet, for the tv boxes.
you have to wait about 15 minutes for your mac address to expire before you can pick up a new address using a different piece of hardware, or you have to clone the mac.
yes it works.