Media company Viacom Inc said it will reorganize three of its domestic network groups into two new organizations as part of a restructuring to drive growth. The company, which owns networks such as Nickelodeon, MTV, VH1 and Comedy Central, said it will take a related pre-tax charge of about $785 million in the quarter ended March 31. Viacom said it expects to save about $350 million annually after the restructuring.