Maybe just try disabling uPnP and power cycling the router for a few minutes.
Check router for a firmware upgrade. If the router supports Custom Firmware like DDWRT you might consider giving it a try. Some of my friends have multiple Battlefields going in the same house and they use DDWRT.
We use a FreeBSD firewall as a router and it lets us play all our games together. Some extra settings needed flipped around that most other routers don't have I doubt (like static ports).
