Ultralink Microphone ULM300USB to two speakers


I have two Behringer B115D speakers and an Ultralink ULM300USB microphone.  I love Behringer's feedback cancellation technology here.  I figure there are some smarts in the speakers that subtract the incoming XLR signal from the mic's signal, so you can place the open mic right in front of the speaker with virtually zero feedback.

But the mic vocals only come through the one speaker that I've plugged the USB receiver dongle into.  I know I could plug the USB dongle into a laptop and route it through to both speakers from there, but this would lose the benefit of the feedback cancellation.  So I'd like to hear the mic vocals through both speakers, without losing the feedback cancellation.

I wonder if I might be so lucky to find that simply buying another ULM300USB would fix the problem?  I'd then have two receiver dongles, which I could plug into each speaker, and fingers crossed, the two mics will then transmit simultaneously to both receivers.

I wish I was that lucky.  I bet each unit has a unique frequency or signature so they only pair with the dongle they were sold with.

What are my chances of a win here?  Anyone actually tried this?