The reason is the bigger the dining package, the cheaper each meal is. If they could be shared, I could buy a dining package for 8 nights for myself, and hand them out to my 7 family members, and each would be significantly cheaper than if we paid for each meal oop. So there is no sharing, even if it just 4 dinners. NCL would rather you purchase specialty dining for the 2 who don’t have it than let you share.