How to create a conditional relationship for a column?

Question

I have a school which runs different classes during summer and winter. ClassroomSetup 1 & 2 have parallel data structure. Every day has a switch to set the classroom setup. So when switch == 1, the school has classroomSetup1, when I call the related Teacher object which is 1-to-1 relationship with Classroom, the TeacherSet1 data will be achieved. When the switch == 2, then, the ClassroomSetup1 object will be ignored, only ClassroomSetup2 and TeacherSet2 objects will be chained up when called. How to achieve this data model in Power BI?

ps. I am here only simplying my scenario. The actual situation is like the latter attached picture I have a long chain of related tables, and each table has a lot of columns to map with the switch. Is it possible to avoid creating a new columns for all chained tables and multiple columns of each table?