We have two AAD/Office 365 tenants, and I've heard that Azure B2b might be what we want, but I'm not currently sure if it is capable of what exactly we're looking for.
We have users in tenant A with @domain1.com accounts. It is here that we've built a SharePoint site collection. SharePoint Online specifically.
We would like to grant visitor/view access to all current and new users in tenant Bfirstname.lastname@example.org users so they can view these sites.
Essentially, is there a way to grant anyone with an @domain2.com account automatic access without the email invitation/redemption process? @domain2.com users are also already Microsoft accounts (work/business accounts) and we control this tenant as well.
Then beyond that, is there a way to have this auto-access on a specific site and all of its subsites/pages, but exclude that access to other sites in the same collection? We would want @domain2.com users to have access to only parts of the Site Collection.