Thanks for that! I was hoping something like this existed so I could do the car audio aux + gps + charging.

Is there an opposite version of that, like one I could attach to my headphones and play through an iPhone?

EDIT: found it - https://www.amazon.com/dp/B01HQ0UVTG?psc=1

Well, the one I have does that. The silver thing you see in the image can be removed as it's just an adapter. Then you have the normal aux connection.