Headset Splitter for mic as well?

I see alot of headphone splitters that appear to allow you to share your music with someone else. I'm wondering if anyone knows of a Y splitter that will allow dual headsets so that I can take advantage of the recording apps to conduct interviews with my iPhone. I want to use two headsets jacked in to record voice from 2 people. Or use it to conference call with another person standing right next to me and someone else on another phone.

Does anyone know where to grab a headset splitter vs just a headphone splitter?

Thanks.
A.