So I dont know if this would work with your group but we did work mats. Each child had a mat and a table space (usually far enough apart that they couldn't touch or reach anyone else or there space). Whatever material they were working with would go in a basket (Only x amount of crayons, legos ect so others can use it too) and they would sit down and keep their parts on there mat. If it went off there mat, it went away. Seemed to work well. I do this with my 2-3s too.

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