Maryland Code, Alcoholic Beverages and Cannabis § 6-311

(1) purchase any alcoholic beverage except from a licensed manufacturer or wholesaler, private bulk sale permit holder, or nonresident winery permit holder;

(2) sell any alcoholic beverage to any other retail dealer except the holder of a Class C per diem beer, beer and wine, or beer, wine, and liquor license; or

(3) keep or allow to be kept any alcoholic beverage on the licensed premises except those that have been purchased by the retail dealer.