[Michael Romanos]

It is common for dogs to want to protect their own special given things - especially "live" things like meaty bones and chew bars and the like. My suggestion is make sure thay these items are in different rooms or areas of the house and outside the house so that each knows where their own possessions are. Don't feed the Corgis together or have their food and food bowls in the same room.
It is unusual for BOTH Corgis to react the same way when you or your other family members are giving them special treatment such as fondling and holding.
But because it is only at a superficial level, I would expect this kind of behaviour to wear away sooner rather than later. It all depends on the human mannerisms in regard to body language and vocalising and things like patting both at the same time or getting another member of the family to caress one while you are caressing/handling the other.