Yes it is possible to end up with a property in each name and avoid the stamp duty issue. The way to do it is after the subdivision into two torrens titled lots, which means at this point both names on two properties, a deed of partition will need to be executed which effectively means that you both transfer your interest in these properties to each other. You will need a valuation for both properties and if they are equal value all you pay is about $100 to Office of State Revenue and no stamp duty will be payable. Get a Property Lawyer to do this for you but just make sure they are familiar with Partitioning of Land.