Put a different colored dot on each desk in a group. When you need to have one student from each table do something, you can just simply say "Green dots, come get the papers for your table." or "Orange dots, take your table's trash to the trashcan."
Unfinished Work Tip: Worksheets no longer get lost or forgotten with this attractive solution. Give each student a magnetic clip for her desk and have her attach any unfinished work to her clip. Not only will she know where to find the paper to finish it, but it's easy to estimate how many students need to complete an assignment.
Under The Table and Dreaming: Home Office and Work Space Ideas & Inspiration | 75 Creative Desk Areas