Multiple headphones, only one records.

[Diretooth]

So, I'm starting up a Let's Play channel, and have had some success with the whole video and audio capture thing. However, I've hit a snag. My main headset, plugged into the front of the computer via a jack splitter, works fine with little trouble.
However, I'm going to have someone joining me on commentary, and they have a similar headset with a microphone, plugged into the back. The computer recognizes the headset as 'Line-In', recognizes that it has a microphone and earphones, but it neither plays audio through them nor picks up audio from the microphone.
I use Win 7, the offending headset is a Letton headset with jacks, like mine has jacks. The 'speaker' plugs into the green output outlet, as evidenced by an arrow pointing away from what looks like a paragraph symbol. The 'microphone' plugs into the blue outlet that looks like an arrow pointing toward a paragraph symbol. (That is probably not what it really is, but it's the best physical description I can manage.)
I've tried closing out of OBS Studio to make it recognize the headset, I've tried resetting, nothing works. If there's any information I'm missing, let me know, I'll answer as swiftly as possible.
Thanks in advance,

 

[jsmithepa]

Oftentime, a PC has only 1 LINE IN and 1 MIC IN (record), if you have one connector on the back and one front, oftentimes it's designed so when the front is plugged in, the back one automatically disables.

Assuming am right, and you are only recording 2 voices, no background music, you need to find a MIC amp so the second Mic can go into Line In, and the sound card mixer will take Mic In and Line In simultaneously.

The sound device mixer, the one with the many sliders, tell you how many audio inputs you can have.

 

[Diretooth]

Oftentime, a PC has only 1 LINE IN and 1 MIC IN (record), if you have one connector on the back and one front, oftentimes it's designed so when the front is plugged in, the back one automatically disables.

Assuming am right, and you are only recording 2 voices, no background music, you need to find a MIC amp so the second Mic can go into Line In, and the sound card mixer will take Mic In and Line In simultaneously.

The sound device mixer, the one with the many sliders, tell you how many audio inputs you can have.

Given that I will be doing Let's Plays, I will be recording game audio at the same time, while recording video.
Currently, I have it to where game video, game audio, camera video, and voice audio are being recorded. I want to do another microphone so the other speaker can be heard.
I have tried plugging my main headset into the back so I could test if it is working. It did not.