I think the separate feeding stations are a good solution.
Some dogs just aren't going to share with each other; they may share with other dogs but for some reason they just aren't willing to share with that particular dog. Bimmer will let Kharma eat out of his dish on occasion, but never, never lets Shiva. I can understand it, 'cause Bimmer and Kharma are both nibblers and eat just a bit at a time unless they are extremely hungry. Shiva, on the other hand, eats until it's all gone.
It's probably a good idea - if you don't do this already - to make sure that Addie and Hammie are both used to you taking things (food included) out of their mouths, holding it for a few seconds and then giving it back. I don't expect my dogs to let anyone but Charlie or me to take food from them, but they understand that if we want to take it they are to give it to us. They're a bit reluctant sometimes, and it's hard not to laugh when Shiva and Kharma try to hide stuff up in their jowls so we don't see it, but they comply with no quarrels or grumbling. Whining, maybe, but no grumbling. (g)