(a) every intermediary shall be treated as a separate unit;

(b) if two or more intermediaries hold an estate or any interest therein jointly, the share of each intermediary in such estate or interest hall be treated as a separate unit: Provided that where any such estate or interest is held by a Hindu joint family consisting of a common ancestor in the male line and his descendants, the family shall' If the common ancestor was alive on the vesting date, be treated as one unit;

(c) if an intermediary holds shares or interest in two or more estates, the aggregate of his shares or interest in all such estates shall be treated as a single unit.