Suellen Tunney gazed out the french doors toward the stone terrace of Wölffer Estate Vineyard in the Hamptons last summer and saw noisy groups of women in tiaras, sashes and “Bride Squad” shirts. Some chanted, “Ro-sé, all day! Ro-sé, all day!”

“They would literally be doing a pyramid of women in the vineyard,” says Ms. Tunney, retail-sales director at the Sagaponack, N.Y., winery known for its rosés. “You would have bridezilla after bridezilla.”

Wölffer...