If I have a team that's played 10 games, how would I create a report to show the overall stats for games 1-4 or games 3-6.

Here are the steps:

1. Duplicate the "Overall (Last 5 Games)" report and select the duplicated report
2. Go to the Reports -> Edit Reports... menu item (or just double-click the newly created report)
3. For games 1 through 4, Replace the "Additional Instructions" field with the following text:
   
   WHERE s.gameID IN (SELECT g.id FROM games g ORDER BY g.gameNo LIMIT 0,4)  
   GROUP BY p.ID
    
4. For games 3 through 6, Replace the "Additional Instructions" field with the following text:
   
   WHERE s.gameID IN (SELECT g.id FROM games g ORDER BY g.gameNo LIMIT 2,4)
   GROUP BY p.ID

NOTE: This is assuming the GameNo fields for the Games are consecutive and correctly named.