Binding specific IP with OpenVPN

Hello,

I was hoping someone here could shed some light on my current setup.

I am running an OpenVPN remote access server on my router. When I originally configured it, I was not able to find a place to specify what interface to bind the server to, just an option to change the port. The server was listening to port 1194 on each of my WAN IP’s. This was fine for the time being, I simply made a firewall rule denying tcp:1194 on all the WAN IP’s except for the one I wanted.

Can anyone tell me if it is possible to specify the IP for OpenVPN? I have a few users being NAT’d behind the router, and I’d like to open all ports for them. I imagine I could create a rule that has a higher priority, but I would much rather tackle this issue at the source.

Thanks in advanced.