How to control exteranl web page elements RPC

So here's my issue. I have a web page that i created in Adobe Edge. Inside the Adobe Edge site I'm loading a unity.html file when the user clicks a button (this is from within the edge file). This all works great but how do I tell the the Unity.html page to control elements in the Adobe Edge web page. For example, in my unity.html file, I'd like the player to click on an object and have the buttons in the edge file to change. I've looked into RPC but all ive been able to do is window.open.

Thoughts,

Z