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It is possible with this mod. Just it does a lot more.http://custom.simplemachines.org/mods/index.php?mod=610 for example lets you control a group being able to see and enter the board - but that's all it does. It doesn't allow you to stop people entering boards if one or more of the groups they have access to would allow them in.Mine allows you to set up whether a group can view and enter the board, and additionally (what it was made for) stopping people entering boards.