Failover between two pfSense boxes

[Eugene]

Hi!

2.2.2.1                    2.2.2.2
1.1.1.1/24 LAN          –----------------------------              4.4.4.1/24
---------------pfSense1                                        pfSense2--------
                                ------------------------------
                                3.3.3.1                    3.3.3.2

I want to reach 4.4.4.0/24 from 1.1.1.0/24 reliably .
Loadbalancer is set up on pfSense1 in failover mode - first choice 2.2.2.1 link.
Is it possible theoretically without NAT on pfSense1? What should I set up on pfSense2 to route 1.1.1.0/24 back to pfSense1?
Thanks.