CoovaChilli captive portal to support 1:1 IP Natting

Hi, I currently have a Coova Chilli setup for inflight connectivity. The application is connected to the passenger network through the wireless access points. THe coova application runs on a KVM Virtual Guest (in a KVM). For ease, call this COOVA VM. Now, there is another Internet Gateway VM, lets call it WAN VM. The current Coova VM does a NAT of many devices to one. All passenger traffic is routed to the Coova VM gateway interface as a single IP address. Now, my requirement is to move to a 1:1 IP mapping. The passenger devices now must have individual IP address routed out from Coova VM to the WAN VM and not through a single Coova router IP. Please advise how this can be done. I would be happy to engage the right expert.