Use Group Moderation Setting is a checkbox available for Moderators to set on every group member's individual "page". It is the default setting for all group members unless a different Posting Privilege is selected.(Override:...) It is also one of the options available in the recently implemented Members List filtering capability.
However, a new Owner or Moderator trying to find that setting might have a hard time because it is not named as such anywhere in the Settings page; under Settings > Spam Control it appears as Message Moderation.
Can I suggest that the words Message Moderation be replaced by Group Moderation Setting?
This also has implications in the Owners Manual. Message Moderation (as in the context of the Settings page) is set out in para 3.5.3 (pdf version) but without any mention of it being the Group Moderation Setting. The words "Group Moderation Setting" do not appear until para 11.6, followed by 14.1.3 and finally in 14.4.
IMHO it would be much clearer (mainly for new Owners & Moderators) if para 3.5.3 was titled Group Moderation Setting as well.