Embed Unity game in a ViewController within my ios app.

I need to display my unity game within my ios app. My app has a main view and there are toolbars as subviews of that view. I want to put my game in a subview of the main view too, but I can't figure out how? I looked through the unity code and it is creating a window for unity, but I need it to be a view. I also need my toolbar and unity to be enabled (i.e. touchable) simultaneously. As a simple example of what I want to do--I want to be able to click the "red" button in my ios app and that changes the color of the ball in my unity game. I know this could all be done within unity, but I have extensive ios code that I do not and in some cases cannot re-write. Thanks for the help!