Grandfather's property is not ancestral property.
The partition what you intend to do is nothing but your family arrangement.
Since is it mutually agreed by everyone, it has its own legal validity.
As per law, if a married woman receives a property whether immovable or movable, it becomes her own property.
The source of income for this property cannot be questioned, nor the donor can be challenged for the transfer of the property by a gift deed to the married woman, it becomes her own and absolute property as per married women property act.
First of all you read the law properly in this regard especially about the definition of ancestral property, do not pass sarcastic comments on the basis of your half knowledge about law.
You better consult a proper and experienced lawyer in the local before jumping into a predetermined conclusion. This will help you solve your problems, save your money, energy and time if at all you are trying to wage a losing legal battle on the basis of your own understanding and notion about the law of the land.