Group Discussion - some posts going to main discussion, others to groups

[bhaus]

I want to have group discussions go to the main thread of the discussion. This works for some groups, but not others. For example, some groups are able to post directly to the main thread, and others are only able to post to their group. So, all groups cannot see each other's responses.

How can I ensure I get one result, to post to main thread only (for group grading and viewing)? I do not want to do a non-group each student to participate since it is group-led work.