How can I use 2 USB Headsets on one Macbook? I homeschool my daughter and she takes several complex online classes.  The teachers want me to be able to listen in and also be able to talk from time to time.  I tried going without a mic, but there is way too much background noise for the listener.  Recently, I purchased two Turtle Beach Ear Force PLa Gaming Headsets.

While they each work great individually we can't use them at the same time because, the Macbook makes you select a specific USB port. Is there some sort of USB splitter out there that would allow us to both plug into one USB port?  When we just had to worry about headphones and not a microphone, we used a Belkin F8V234AMOB 6-Inch Audio Y Cable. My hope is to find something similar for USB ports, but I'm open to other suggestions.

Thanks in advance for any and all advice!
You don't need special hardware for this. Plug in both headphones, then open Audio Midi setup from /Applications/Utilities. Click the plus in the lower left corner and choose "Create Multi-Output Device." Check the checkboxes beside both headphones in the new panel on the right. If you want to rename it, you can double click the new entry in the list on the left and give it a name like "Both headphones."

Now you can choose the Multi-Output Device as the audio output in System Preferences → Sound. (You can also easily change the output by holding the Option key and clicking the volume menu.)