I have separate Test Runs covering different Oracle modules (Order Management, Purchasing, AP). Is there any way to report across all three?
Yes, there would be multiple options for this. First of all you could think of assigning them all to a milestone to see all statistics for the testing phase/milestone combined. For future test runs you could also think about grouping them together in a test plan (moving existing runs to a plan is currently not possible):
You can also take a look at the reports under the Reports tab. E.g. the Run Summary reports allows you to select multiple runs to create a combined report.