Can be done
That is do-able. You can get the same drafted by an advocate for precision or you can do it yourself as well but I would suggest an advocate as the drafting will make or break the ambiguity in your will which can either raise or decrease the chances of disputes. Registration of will is not mandatory but I would suggest the same.
Further, if you need help with the drafting, feel free to contact me on 7601090381 or firstname.lastname@example.org