Load Balance/Failover

[bstamper]

I have a need to try to provide both Load Balancing/Failover for a couple buildings.  My topography is like this:
I have 2 buildings today.  Both buildings have their own Mediacom Cable modem connection.  Today the setup is simply that both buildings have their own pfsense box and there is no connectivity between the buildings.

We've run fiber between the buildings now and will be tying the network together.  Both buildings are on the same 192.168.10.0/24 subnet on the LAN side.

My goal is to allow each building to use their own pfsense box and respective internet connection to get out and yet allow failover/failback if one of the pfsense boxes or internet connections were to die or go offline for some reason.  The reason for not just using 1 and letting it failover is that I don't want to saturate a link possibly and pay for and waste an internet connection.

Any ideas on how i'd set this up in pfsense.  Setting up the CARP was simple and I can get the boxes to failover to eachother but using a single Virtual interface forces one box or the other to be the DFGW and thus I only end up using one of the 2 internet connections.

[bstamper]

I've found one solution to this would be to vlan each of the buildings and trunk ports to the LAN side of the FW.  Set the priority for each building's vlan to keep the gateway local.  Anyone else have any other ideas?