The Montgomery County Commissioners are setting the bar high for health care management companies interested in buying Parkhouse, the county nursing home in Upper Providence Township. They approved issuing a request for proposals Thursday. County officials say taxpayers as well as Parkhouse employees, residents and their family members would all need to be convinced that a change in ownership is for the best. The facility has almost 500 beds and about 700 employees. The 15-acre county park across the street from Parkhouse would not be affected by the sale of the nursing home and would remain as is.