Snowdrops in February

The bubbles we had formed at school turned out not to be workable. We work with ever-changing group settings, because the children receive education at their own level. A child may be in a different level in reading comprehension than in spelling or math. Now we form bubbles inside the classrooms, groups 1.5 meters apart. There is a lot of shifting and cleaning in between the instructions.
I doubt whether this can be sustained.