LG Group, the country’s fourth-largest conglomerate, announced its year-end executive reshuffle on Friday, seeking to infuse the top brass with younger blood. From Wednesday to Friday, affiliates of LG Group held board meetings to appoint three new chief executive officers and promote 136 executives. Among the 99 to become executives, 97 of them were born after 1970 and five were born in the 1980s, the conglome.