Need help setting up static route on LAN

[tuaris]

Setup Overview

As seen in the diagram below I have two offices.  Office 1 has a single LAN (192.168.0.0/24) and Office 2 has a single LAN (192.168.8.0/24).  The two offices are connected to each other using a site-site IPSEC VPN tunnel using OPNSense A and C.



Office 1 has two ISP's.  OPNSense B is connected to the second ISP and there are some hosts in Office 1 that use OPNSense B as the default gateway.

Problem

I would like to make it so 192.168.0.50 can communicate with 192.168.8.2 and 192.168.8.2 can communicate with 192.168.0.50 without having to configure a static route on 192.168.0.50.

Attempts So Far

I created a static route entry on OPNSense B to send anything for 192.168.8.0/24 to 192.168.0.100



This does not work as expected.  The hosts can ping each other, but no network traffic other than that makes it through.  For example, HTTP does not work between them.

Firewall rules for LAN on all OPNSense's:



For the IPSec interface on OPNSense A and C: