Do you assign roles like “materials” or “group leader” when students work in groups? Why not assign "Math Practice 5: Use appropriate tools strategically," instead?
These group roles assign each student a Math Practice Standard in order to focus their participation within the group.
In my classroom when we work through an activity, I put my students in groups of 4 and pick the 4 most relevant Math Practice Standards for the day. Each group member has one Math Practice Standard to focus on and these cards lead the student through what kinds of questions they should ask, what to specifically look out for, and how they should encourage and lead their teammates.
Use different combinations of the 8 Math Practice Standards depending on the focus of the task at hand.