Kansas City (Mo.) Firefighters' Pension System hired Essex Investment to manage $30 million in active domestic large-cap growth equities, said Rick Boersma, executive officer. Essex replaced Goldman Sachs, one of the finalists in the search, Mr. Boersma said. Trustees of the $375 million plan wanted a more aggressive approach with that portfolio, he said. MFS also was a finalist. Callan Associates assisted.