San Francisco The newly formed health care services giant, McKesson HBOC Inc. , began operations in January after shareholders approved the $13.5 billion me rger of drug distribution company McKesson and home care software manufacturer HBOC.

Four HBOC executives have joined McKesson's corporate officers on the new McKessonHBOC executive operating committee. Charles McCall, chairman and chief executive of HBOC, is now chairman of McKessonHBOC, and Albert Bergonzi, HBOC president and chief operating officer, is group president of health care information technology. David Schenk, former senior vice president of HBOC's enterprise services, is now senior vice president of the affiliation team and Christine Rumsey, HBOC senior vice president of human resources and administration, succeeds William Armstrong, who retired after 26 years in that position with McKesson.

In addition to McCall and Mark Pulido, president and CEO, eight other executives have been elected to McKesson-HBOC's board of directors. They include Alfred Eckert, Tully Friedman, Alton Irby, Gerald Mayo, James Napier, Carl Reichardt, Alan Seelenfreund and Jane Shaw.-M.L.