Creating a nested sort before placing the grade levels on the page shelf is probably the best option. The following KB article provides information on how to do this.
Hope this helps!
Thanks Tracy. I did get the sort to work with sets, but it still leaves the issue of the axis displaying schools with no data. Any thoughts on that one? I feel like I'm trying to do something that may not be possible. Maybe I just need to stick with filters.
Pages are designed to show the combination of all the dimensions at once, so you can quickly "page" through the variations using whatever is on the Pages shelf. To do what you want, filters are the best option at this time.