How do I connect two headsets for a Smash tournament?

I will be running a small tournament next weekend, but I’d like to be able to offer headsets for the players since I already have two Kunai Universals. The instructions recommended plugging the headset directly into the tablet/gamepad. I can get a splitter for that, but I’d rather be able to use the inline remote so people can adjust audio. What are people doing at tournaments? What’s the best way? Thanks in advance.