.1. first you 3 have to identify which floor is to go to whom
2. once that is agreed mutually between all 3 of you, then you can record that in writing by executing a Deed of Family Arrangement
3. once the above deed is signed between you 3, then for each floor, the other 2 parties will sign release deed in favour of the party to whom that floor is allotted under the deed of family arrangement
4. for example, if 1st floor goes to you, then your brother's wife and wife will execute release deed in your favour, therein releasing their rights in the 1st floor in your name
5. similarly release deeds for other two floors can be executed
6. have all the 3 release deeds registered
7. now the property of each of you is duly identified under the Deed of Family arrangement and the release deeds
8. now each one of you can make a Will in favour of the beneficiary i.e. the 3 sons
9. the property will be transferred to the sons' names after the demise of the testator i.e. the maker of the Will
10. if you want to avoid any future disputes between the 3 sons, then if those 3 sons are majors, they can also be included in the Deed of Family Arrangement and the floors can be distributed between them therein. So transfer in favour of sons will happen in their lifetime itself and any future disputes can be avoided
11. terrace is a common area which can be enjoyed by each son. However if you wish to make a Will of that too, then it can be included in any of the 3 above Wills itself. No need for a 4th Will
12. A joint Will of 3 of you will further reinforce the Deed of Family Arrangement and consequent release deeds. But in order to avoid any confusion it is better that separate Wills are executed