Each act is adjudged separately on their own merits, however, they can also be connected. In your example, if the lead runner stopped running as a result of the obstruction and the trailing runner could have achieved third but stopped at second base because he saw the runner in front of him return to third because of the obstruction, the umpire could grant the lead runner home plate and the batter runner third. However, if the batter runner was obstructed rounding 1st and the lead runner was obstructed rounding third and subsequently thrown out on a close play at home. Time would be called, and the runner from third would be awarded home, and the batter runner would be awarded second.
