How to Create a Coherent Interface for a Large Product

I wonder if it's possible to create a coherent interface for a large product with lots of different teams working on one thing. I don't know what the solution is to achieve that, unless it's just basically you and a couple other people working on it. It's not possible to make anything coherent once you've got past X number of people,. Because it's like too many cooks spoil the broth situation.