jleeper:
Appears your question got lost in the shuffle.
It sounds like what you need is a prameter based query.
- Start out with a simple select query that pulls all of the data in that you want to show on your graph/chart.
- Create your graph and set the formating etc...
- Now change your query so that is uses parameter(s) to make the selection (Mr. Browne has one such example
Limiting a Report to a Date Range. I'm point you to this example anticipating that you'll need to limit date ranges in addition to the school.)
Best of Luck