Jail on NIC with no address

My FreeNAS box has 2 NIC ports, one is on my LAN, and the other I want to use for Jails that will be on the WAN. My ISP provides me with 5 static IPS and my current Gentoo server (that I want to replace with my FreeNAS server) just aliases them all except one that is used to let my WAN access the internet through a dedicated router. My Gentoo box currently has complicated firewall rules to keep WAN access off the LAN.

I would like to do something similar with FreeNas using jails (3 jails 1...

Jail on NIC with no address