You wouldn’t really want kids sectioned off because you wouldn’t be able to monitor all students at once. Plus even if you were able to put up, for example, a carpeted bulletin board to absorb sound, it may not even be enough to make a difference = sound would go over the partition and be heard by others. If you have a large room, put groups as far away from e/o as possible and ask them to play softly, gather in a circle. If you have a smaller room have groups take turns practicing; others do an assignment / something else. Just my thoughts.