They can't turn you away! As far as Im' aware, you just book in like anyone else so they have all your info, but don't do your ante-natal apts ther (and hopefully never set foot in there again at all). So it's not actually shared care, it's just a matter of them having you on record so if you do need to transfer you're already on their files.
All the best for your upcoming birth! Hope it goes wonderfully for you