You could try hooking them up to another speaker that has the input connections. I have done this before with several different speakers and daisy chained the connections with several speaker connections and they worked great. I had surround sound all over the room. You might run into a problem with the main speaker that you plug into not being able to push all of the speakers that you have but you might get lucky. Those speakers say that that carry 550 watts.
I recently bought a set of speakers that stated that they push 100 watts. The sub was putting out 50 watts and the others were only putting out 25 each. I hooked up a 100 watt speaker to it and it worked. You might be able to contact logitech to get the other speaker that you need. That set of speakers looks awesome on the site. This
is the specs for the other speakers
I think that this is what you wanted to know. If it was not your solution, let me know. I will help you more. I might not be understanding your question correct. I have referred your question to someone on the site that works with logitech.