Seems that GroupsUsers is already deprecated, and Permissions seems the way to go. GroupUsers has an interested option : the "no-interaction" permission, which disallow any interaction with the world (destroy block, pick item, use furnace, etc.). With GroupsUsers my server works like that : - by default all users are members of the "Default" group, which only allow to "visit" our world - all registered members of our community are members of the "Member" group, which has standard permissions So, for this system to work with Permissions plugin, we need a standard permissions plugin which will allow to set interaction permissions only for the Members group. Thanks for reading.