I`m trying to accomplish the same thing, can`t. Here`s what I did, what worked, and what did not work. That might help you, and might help people help you (and, think of it, it might help me too!)
- I setup a Linux server at some hosted place with a route that basically says: 192.168.1.0/24 via 18.104.22.168 (the public IP of pfSense B)
- configured pfSense to accept all connections from that Linux server
I can ping 192.168.1.x from that server, which is on a totally separate network! Everything works fine.
Now, I have another pfSense (call it pfSense A). I want, from that pfSense diagnostic "ping" screen, to be able to ping 192.168.1.x. I can`t. I can`t setup a route, because the route needs a gateway, and that gateway wen being created, needs to be on the same subnet as my pfSense A public IP (which isn't 55.55.55.xx)
Is this what you are trying to do too?