I won't shit on you because I was hoping for something similar until I realized that it was the antithesis of the fediverse. Your community is essentially shotgunned out to everyone listening, anyone listening can see and interact with posts of your community. Remember it's not just Lemmy, or Lemmy WebUI, or a specific app, or even forum style apps - the fediverse means anyone on any app can see your community any way they choose.

The only way to prevent that is by disabling federation of your one community, locking your users to only lemmy.world users. For privacy either you want an instance-specific (private) community, or you should look at private forums without federation.