So, now that we have it on board that 1) suppression is a dangerous game 2) maternal styles that use suppression have been shown to have detrimental effects on puppies' temperaments and emotional stability, and 3) resource guarding from other dogs is 100% normal dog behavior, we can move forward with suggestions for how to handle this:
Number one, do not allow the puppy to practice the behavior. Separate out that puppy when you feed. For whatever reason, the puppy feels his food supply is threatened and you need to provide him food safety.
Number two, double up on the resource guarding protocols show in Puppy Culture. They will not necessarily transfer to other dogs, but they will allow your puppy to build up trust in you around food, which right now he does not have.
Number three, if you have good adult dogs, do a lot of sessions where the adult dog gets a treat, you count to one, and then you give the puppy a treat. Wait 3 or 4 seconds and repeat. This must be done with only those two dogs present, and you have to be very crisp with the events. Hold treat hand at your chest. Bring it forward and feed adult dog. Bring it back to your chest and count to one. Move it down and feed baby dog. Put hand back on chest and count to 3 or 5 seconds and repeat process. VERY IMPORTANT only the puppy and the good adult dog should be present when you do this protocol - don't try to do it with a bunch or dogs or puppies milling around.