Issue trying to get Call of Duty WW II to work with multiple xboxes on one network.

We are operating on a network with a Meraki MX64 router. We do not have the option for uPNP but we enabled port forwarding and we have our Xbox ones getting an open NAT type. However, when we launch COD WWii, the first person to log in gets a moderate NAT type and the other xbox gets a strict NAT type. It appears that both are trying to connect on port 3075 according to the text on the side of the console info. Is there any way we can work around this without having uPNP available to allow both xboxes to play and join teams on the same network?