We do that decision-making inside the web servers. It only affects the client you get, so when someone requests a page we do a lookup on the logged-in member t

We do that decision-making inside the web servers. It only affects the client you get, so when someone requests a page we do a lookup on the logged-in member to decide which channel they get. API reqs don't care what channel you're on. No need for any fancy nginx proxying/etc.