Maryland Alcoholic Beverages Section 12-101

      No holder of a manufacturer's or wholesaler's license, and no distiller, brewer, rectifier, blender or bottler of alcoholic beverages or the owner of any interest in any distillery, brewery, rectifying, blending or bottling plant shall be permitted to enter into any agreement with any retail dealer, the effect or purpose of which is to limit the purchases or sales of any such retail dealer to the products of any one or more of such producers, it being the intent and purpose of this article that every retail dealer shall at all times, be and remain free to purchase the alcoholic beverages sold by him, from any holder of a manufacturer's or wholesaler's license issued under the provisions of this article.