Threads do impact each other. There is a distinct order to threads, but we do not follow it in our time. We could, potentially, write Thread A that happened three years before Three B in opposite order. They do affect each other, but we can post at different places.
Since we don't have different forum locations (IE a forum for the manor, then for London, etc) we can keep threads together - if they decided to go to Africa, we could keep it in the same thread.