Hi Kasey,
Unfortunately, team name isn't available in the report builder for grouping (annoying right!?). You could get to the team name by writing a text mode grouping in your report, however you wouldn't be able to show this grouping in a chart.
The best way to achieve this would be to create a calculated field to return the team name and attach it to your projects via a custom form. This field would be available for grouping within your project reports. The calculation you use will depend on how you are defining the team (i.e. is it the Project Owners team, or the team of the person who created the project). Assuming that you are defining team as the Project Owners Home team, using the the text mode 'Owner.Home Team.Name' in your calculation would work.
Does that help / make sense?
Best Regards,
Rich.