3. Nothing in this Act shall- (a) affect any special family or local custom having the force of law, or (b) vest in a son's daughter, daughter's daughter or sister an estate larger than, or different in kind from, that possessed by a female in property inherited by her from a male according to the school of Mitakshara law by which the male was governed, or (c) enable more than one person to succeed by inheritance to the estate of a deceased Hindu male which by a customary or other rule of succession descends to a single heir.