Under a new program, the fiercely competitive Harvard teaching hospitals have agreed to pool some of their research efforts to shorten the time it takes to turn discoveries into treatments. The individual hospitals now receive separate grants worth a total of more than $20 million a year for their own clinical research centers, but now the money, $117.7 million over the next five years, will go to Harvard Medical School, which will award the money to teams of researchers spread among its various affiliated hospitals.