Does NAT exemption in Neutron exist?

With nova-network, DMZ_CIDR existed as a way to perform NAT exemption on a per-destination-network basis. There does not appear to be an equivalent to this functionality, specifically when utilizing a Neutron router and floating IPs. We'd like to maintain the ability to exempt hosts from NAT when communicating with remote networks over a VPN (regardless of whether the instance has a floating IP or not).

Thanks,
James