Start with a property lawyer. You’re going to need one in the end to do all the legals. They will advise you what needs to be done.
A bid hurdle will be getting approval of the local council. The land will needto be subdivided, and it needs to meet certain requirements resize amongst other things.
Also both lots will need to agree to the separation and to pay the other small costs.
Another solution would be to engage a strata manager. As an impartial observerthey xcould structure the existing strata to be functional.