Multi-WAN, Multi-LAN single subnet

[denizen]

I have four NICs partitioned to two LAN and two WAN segments, but having successfully set up multi-WAN with single LAN configuration I now want to set up the remaining NIC to server another physical LAN segment. I also want the opt2 interface serving the second LAN segment to stay within the same subnet of the first physical LAN NIC. Below is a diagram of how I would want it set up.

{ 10.0.3.1/24 }                  LAN1 is connected to a switch serving a plethora of devices.
  LAN1      LAN2                    LAN2 is connected to a dedicated file hosting server, but would be set up with a switch in the future.
    |            |
    |            |
    +          +
    [pfSense box]
    +          +
    |            |
    |            |
  WAN1      WAN2

I'm beginner at best when it comes to firewall configuration and networking. I got most of the basic concepts, but I'm not sure what and how would be the best way to set this up.

[heper]

you need to bridge the lan's to accomplish that. (that way both lan interface become sort of a switch)
search the forum for info on bridge/bridging

[denizen]

Alright. Thanks for the lead. :)