Montgomery County school officials announced yesterday that they are temporarily banning outside groups such as parent-teacher associations and the Boy Scouts from distributing fliers about activities and events in student backpacks. The decision comes less than a week after a federal appeals court ruled that the school system's policy for flier distribution was unconstitutional because it gave educators unlimited power to approve or reject materials. The case is the outgrowth of a dispute between the school system and Child Evangelism Fellowship of Maryland. The group filed suit in 2001 after the school system denied its request to distribute fliers about...