In my district the transition to middle school starts with parent orientation and kids visiting and walking through the middle school classes in spring, and then the 6th year they have 2 main teachers and 1 "special" each quarter. So it is kind of gradual. When my kids were elementary, they had already started rotations among a team of teachers.

Honestly, it's not that big of a leap and the 6th grade teachers have transitioned hundreds of students already.

Good luck- parents can be .... challenging!