Steering wheel controls

I have a 2015 Prius Three with a Nav and backup camera. I've installed an aftermarket stereo and I need help getting the steering wheel controls to work. I have done all of this with the same exact equipment in my old 2011 Prius Two, however, it seems that Toyota changed how the head unit interacted with the whole car. In the 2015, the steering wheel controls media along with the thermostat and second screen THROUGH the stereo. I hate Entune, and I love my CarPlay stereo. But I need a way to get my controls back, I have no way to adjust car settings or trip distance without them working. The last thing I want to do is use the laggy stock unit.. Has anyone figured out or know of a way to bypass the stock system to regain control of the cars infotainment system and climate?