In yahoo groups it can be done if that is what you are asking.
Go to Management
Control Panel
Access Control and there you can select who you want to be able to see the messages. Select Moderator's only and make sure you have the tick mark in the?selection Members cannot view/edit, only moderators can?view/edit.??
A yahoo list owner has contacted me regarding moving her list to groups.io. The one question she had that I could not answer was whether it was possible to completely disable archiving. Obviously, if this is possible, all members would have to communicate by email since there would be no messages maintained on the site, but apparently that had been possible at one time on yahoo. I'm unable to find this as a feature on my own groups. Does anyone here know of a way to make this happen. Cacky