Port forwarding for DDNS

Hi guys can you help with the following.

I have configured load balancing on router board and after that I have another router board in which I have configured Hotspot. So, basically

Internet > Load balancing (3 WAN PCC) > Hotspot

I have configured DDNS on load balancing using WAN1. Now, I want to configure DDNS on Hotspot (using WAN2 on load balancing). Can any of you guys help me in forwarding port for DDNS on load balancer.

Thanks.