Doubt on route creation

Dear, good afternoon.

I have a question about creating routes in openWRT through Luci,

Here's my question:

I have two routers with openWrt, these two routers are connected through a vpn tunnel (openvpn).

Each router is a company LAN network. One is at the company's headquarters and the other at the branch.

The headquarter LAN is 192.168.99.0 and the branch is 192.168.4.0.

Due to the VPN tunnel that we have, I can ping both the head office and the branch network.

In our headquarters, the VPN interface IP is 10.255.200.1, and in the branch it is 10.255.200.2.

The problem is that before the router with VPN that we have in the branch we have a Load Balance with IP 192.168.5.1. I can ping this load balance through the branch network. But I can't ping from the matrix network. How could I configure my routes so that a ping from the matrix network, 192.168.99.0, arrives at the load balance (192.168.5.1).