Atlanta-based Fifth Group Restaurants is about to embark on its most aggressive expansion in the company's 22-year history. Over the next five years, the group behind concepts South City Kitchen, La Tavola Trattoria, Alma Cocina, Ecco, The Original El Taco, Lure and catering company Bold American Events plans to add five new restaurants at a pace of one per year. The plan would grow the company from seven restaurants in metro Atlanta to 12 by 2020. "We feel that the city is such a great place…