Changesets are still visible to members outside of the team area that owns a stream?

I've noticed that Changesets are still visible to members outside of the team area that owns a stream,

For eg:

Mark is part of Team A
Team A owns Stream JUNIT and it's components
Andy is part of Team B

When Mark checks in and delivers a changeset with an associated task,
And Andy opens up the task, and the changeset via that task (eg: changeset #1) he is able to view the files in that changeset.

How can I restrict Andy from having that view access?

Thanks,

KH