Locating documents and sharing them with others within Microsoft Teams channels or chats
Dear Kate,
As an Independent Advisor and community user, I'll help you with your question.
Yes, it is possible, you have to add a Document tab to your team b:
https://docs.microsoft.com/en-us/microsoftteams...
Then you have to give "Read" permission as visitors in the Sharepoint site (Associated to your team A) to your team b:
https://docs.microsoft.com/en-us/sharepoint/cus...
Regards,
Renzo.