How to post a shared comment
Key point: Post a shared comment, only on a document that is in a folder shared between multiple groups.See How to share a document between groups.

Prerequisites

You must have a role of reviewer or higher on the groups, and you are posting a comment on a document that is already shared with at least one group.

By default, comments are posted to the current group. If a document is shared, you can also select the groups that the comment is shared with.

From the document:

  1. Follow steps 1 through 8 in either:
    1. How to post a comment on a document, or
    2. How to post a comment on a fragment.
  2. To the left of the message settings, in the Accessible to field, click change to see the groups that the document is shared with:

  3. Select the checkbox for the groups you want to share the comment with – the same groups are used for all the comments in the discussion.
  4. Click the Post comment button.