Although we all try to be everywhere at once, we can't be! In order to help groupwork go smoother in your absense, have questions prepared for each group. If students are reading, place sticky notes on the corresponding pages where you would like to have students reflect on a question. This way when you do get to their group, they will be prepared to discuss these briefly with you. You can do this with all group work. It helps your kids to become more independent, helps everyone be more productive, and it will save you time.