FIVE PEOPLE died in Detriot early Sunday when their car was rammed from behind by a pickup truck and burst into flames, police said. . . . TWA AND its pilots tentatively agreed Sunday on a four-year contract after more than a year of negotiations. . . . AN OAK Bluff, Mass., businessman was fatally stabbed in the first killing on Martha's Vineyard in 20 years, and his father died after suffering an apparent heart attack while rushing to his side. . . . TIBET'S SPIRITUAL leader, the Dalai Lama, has called off a planned visit to Taiwan this fall, Taiwan's news agency reported Sunday.