Active/Active Fortigate Firewalls as Routing Devices

I'm currently working on a design which will put a pair of Fortigate firewalls in between my default VRF and a number of L3VPNs over MPLS. The firewalls will be located in two different locations on our campus.

In the past, all I have been able to find is documentation on how to setup the Fortigates in Active/Active where they basically act as a large virtual device. This make handling fail-over between multiple locations a challenge, and adds the need to drag L2 networks around my very nice L3 network.

At a conference this fall, I talked with an engineer who had deployed a pair of Fortigate firewalls basically as independent routing devices where session and firewall rules were synced between the devices. I have looked around the Forinet website, but can't seem to find anything there pointing me in the right direction.

I was hoping someone here has deployed this, and could either chat with me about their setup or share with me the documentation they used.

I've done this setup with our Palo Alto firewalls, and I'm really hoping I can do it with the Fortigates. No firewalls would be even better....