title: How do I tell my fulfillment service which device to communicate to?
body: <p>I am working on making a module, which can be connected to a fireplace to add smart home functionality with Google Assistant. I have pretty much everything working, but there is a thing I can't quite figure out.
  I am planning on having multiple devices in google cloud IoT core. To be able to communicate with them, I am using the deviceID. I currently have this hard-coded into the fulfillment code (in Google cloud functions), which is fine for a single device, but how would I go about communicating to different devices from the same fulfillment code?</p>
  <p>I would imagine I have to pass the IoT core deviceID as id in the SYNC intent response, but how does the intent fulfillment know which Google user is sending the SYNC request and which device is supposed to be connected to that account?</p>
  <p>Would this need to be passed to Google home from a third-party app?</p>
  <p>Any help, tips, and insight would be greatly appreciated.</p>