I hadn't realised that it was the Chi that growled first, your Chi is resource guarding and you are the resource. How I handle this sort of behaviour is to get up and walk away so the resource that a dog is guarding is no longer there. I don't say anything, I don't speak and certainly don't shout or yell, I let the dog work it out for themselves, I find it works better if they do. They guard the resource goes, dogs will learn quickly that if they want to stay with you they don't guard.

I have found this the best way to deal with this problem and less stressful for me and my dogs which to me is important.

Hows the situation now