When you say "But the standard group projects people do earlier in schooling do lay the foundations for this kind of teamwork," that's exactly what I'm thinking should happen. As a highschool teacher, I'd be wanting to target these projects in order to foster a basic set of teamwork skills.

Not that everyone needs help to develop them; but if you start at the beginning with highschool freshmen, the ones who already 'get' academic teamwork will be learning the content, while the others get brought up to speed. Hopefully in time for college, where they (ideally) are spending more time on useful or interesting content, and are assisted by already having the skills down pat.