I just signed a permanent alliance deal with another civ, and we were both building 3 of the same wonders at the same time. The turn after I signed I get messages that I cannot continue building any of them, so it seems my new partner automatically gets dibs on them? I know we'll both get the benefits anyway so it doesn't really matter in that respect, but I was further along in building all of them, so this way there's more of a chance of someone else building them first. Does this always just happen automatically, or is there some way of influencing which build is allowed to continue? On a related note it also made me think, what happens to national wonders? Are we still allowed to have one each, or does one of those get deleted too?