Use colored dots to make groups easy. Put a different colored dot on each desk in a group. When you need to have a student from each table do something, you can simply ask for all the green dots to bring you the papers from their group.
This a post about how a teacher organizes her data for her students. I think it would be easily transferrable to be used for an SLP. It would allow an SLP to have all data organized in a binder, making it easier to keep track of everything.
<p>Dress up a cheap-o plastic plate drying rack with pretty washi tape, then take advantage of those dividers to organize important files. (Credit: <a href="http://www.theorganizedclassroomblog.com/">The Organized Classroom</a>)<br /></p>