Multiple gateways across wireless network

[nexus010]

Hi I have tried to find all I can on setting up a multiple gateway scenario across my wireless network.
I have a 10 meg cable modem and 10 meg fiber connection.
Is it possible to set them up to load share or for failure back up or better both across a wireless network ?
Currently there are about 10 km between the 2 (pfsense) gateways and so I need to do this on the same subnet.
Or if neccassary on a dedicated vlan through the same link (with L2 switches)
I can't find a similar setup in the forum.
Any help would be appreciated
Cheers