How to Listen for SSDP replies on multiple interfaces using IBM BlueSocket

I am using SSDPClient and BlueSocket for discovery of some NAS devices.

Now, I found that with the stock code, I get responses only on the default interface, but not on additional interfaces with their own subnets. I have a NAS on each subnet, and when I make either the default interface, then the device on that subnet responds, but not the other.

I suspect that BlueSocket only listens on the default interface. But I cannot figure out how to change that, because there's no mentioning of interfaces or devices on the source code, and I'm not familiar with the BSD socket functions enough to find how to do that.

I suspect that I need to iterate over all the interfaces, get their IPs addresses and then have the SSDPDiscovery code listen on each of these, to get all the responses. How do I accomplish that?