Place the peaches in a bowl. Combine flour and sugar; sprinkle over peaches and toss to coat. In a small bowl, combine cracker crumbs and brown sugar; cut in butter until mixture is crumbly.
For each bundle, place half of the peach mixture on a double thickness of heavy-duty foil (about 18x12 in.). Sprinkle crumb mixture over peaches. Fold foil around mixture and seal tightly. Grill, covered, over medium heat for 5-10 minutes or until peaches are tender.