I have five groups now. How would you even know someone posted to your group if they already have you blocked. They can still post in your own group.
Most don't even know how to see everyone's group posts. Yet even then you can't block them from your group.
There's no moderator options to block! Nor any moderator options to delete posts. Not even to type in their username or user id number or the post's title or the post's id number.
Yeah I'm familiar with all of that and more.