Have a "Master Lessons" list that is a separate editable reference space, and from that, teachers can select and pull lessons into their student lesson records as the year goes. It would allow teachers to create a shared database of lessons within a school, but then tailor the instruction each year for their students.

Teachers could also create one-off lessons for a year that don't get placed in the Master List but are recorded for the students who had the lesson; or they could add an especially valuable lesson to the Master List for future use.