Disable Conversations in Groups for group members

Yes and no.  Staff doesn't want students to use the Conversation feature of the Group at all.  Now, I know i can restrict the ability to send to the group via their mailbox in Outlook using Delivery Management in Exchange, but I have been unable to find anything that prevents users from just going into Group, going to conversations, clicking "New", and sending a message to the group.   I'm guessing that is because message done this way aren't really being sent by the user through their mailbox, but by the group on behalf of the user (at least that's how it makes sense in my head).    Failing that I would settle for moderation on the group, but I don't think Office 365 Groups supports moderation like DLs do.