I'd consider creating an additional table with 1 record = 1 classroom
In a list type layout, each room record would occupy a separate row of the layout and you can place a portal on your layout that will appear once on each row of your layout.
In your relationship graph, you'd create a relationship something like:
Classrooms :: RoomID = Details :: RoomID
Where "Details" refers to the table holding the data you want to show in each of your portals.
Base your Layout and Classrooms and refer your portal to Details and you've got it.