No, I believe you have to manually add to teams.
Easiest way is to create a team in a repo and then add a group to the team.
Team roles then define access levels to the repo.
I believe that I have found that teams are necessary for limiting access to repos. At least that seems to be the way we got it working in our setup. Been awhile since I worked through that. As I recall, the documentation was slim and i sort of just stumbled into it. I had been reading through the security documentation so might be something in there.