Dell ( DELL) is breaking its commercial-business group into two divisions, and the current head of the unit will retire in March, according to published reports. Joe Marengi, the general manager of Dell's commercial-business operation, has decided to leave the company. The commercial-business unit oversees Dell's personal computers and servers. One of the new units will focus on the education and health care sectors. The other will continue to be known as the commercial-business division and will concentrate on serving large corporations, the reports said. Shares of Dell were down 24 cents at $27.02.