Overland Park, Kan.--Ron Wall, president of Primedia Business Magazines & Media, a unit of New York-based Primedia Inc., âhas left to pursue opportunities with a start-up,â a spokesperson confirmed Friday. In all, 12 senior managers at Primedia Business left the company on Thursday. Additionally, Primedia Business reorganized its structure, reducing its eight product groups to three. The moves come on the heels of the departure of Tim Andrews, Primedia Businessâ former CEO, earlier this month. A search for a new CEO is underway.