Improvement to Teams across tenancies

Any new solutions to this yet? I've identified three options which unfortunately do not work for my organization.

1. Applying an exchange address book policy, which would mean they wouldn't come up when searching, but could still be sent messages directly by using full email. But then they wouldn't appear in the exchange GAL which our organization uses to find people.

2.Disable guest access in teams. People would be unable to add guests to teams groups which we need for some users. An all off or all on does not work.

3. Information barriers to block all communication between the users. This will not work because we want some guest accounts to be able to access but we don't want guest accounts to show up in the search because our organizations are external to each other. It also requires A5.