Each winery which enters into an agreement with a wine wholesaler shall designate a sales territory as the primary area of responsibility of that wholesaler which is applicable to the agreement. No winery shall enter into any agreement with more than one wholesaler for the purpose of establishing more than one agreement for its brands of wine in any territory. However, the existence of more than one such agreement as a result of a sale of a winery as contemplated by § 4.1-405 shall not be prohibited. Notwithstanding any other provision in this chapter, a winery may enter into agreements with more than one wholesaler in a sales territory for new brands which are not clearly extensions of existing brands. Territories served by a wine wholesaler on February 18, 1989, shall be deemed designated sales territories within the meaning of this section. Each winery shall notify the Board in writing of all designations of sales territories, the identity of the wholesaler appointed to serve such territory and a statement of any variations which exist in the designated territory in regard to a particular brand. Redesignations shall be reported to the Board within 30 days.