Hi,
The requirement is not clear. Do you want to route traffic from 10.123.236.0 to 10.123.245.0 via tun.1, while sending 10.123.237.0 to 10.123.245.0 via tun.2 ?
If that is the case, you will first need to configure 2 different VPNs (Phase-2), first with proxyID 10.123.236.0 to 10.123.245.0, bind this to tun.1. Second one will be for proxyID 10.123.237.0 to 10.123.245.0, bound to tun.2.
Next, create a PBR (Policy based routing) , with match lists for src-10.123.236.0 dst-10.123.245.0 pointing to tun1. Repeat the same for tun.2 and bind the PBR to your LAN interface.