Washington--The Grocery Manufacturers of America, Washington, said Thursday that its powerful membership is exploring creation of a buying consortium on the Internet. More than 50 of the largest consumer package food manufacturers are behind the effort, which would create an Internet electronic marketplace for conducting sales and auctions, and swapping information. The move is a potential blockbuster because the combined industry spends more than $200 billion annually in goods and services. Consultancy PricewaterhouseCoopers, also Washington, lands in the catbird seat, as the chief adviser to the market. The move follows similar efforts in wholesale foods, automotive, oil, chemicals and other industries.