Even as the warring factions -- the Birlas and Lodhas -- prepare for a long legal battle over Priyamvada Birla's will, sources close to the family say a settlement formula is also being thrashed out.

The formula proposes a three-way split of the Rs 5,000 crore (Rs 50 billion) assets, with one-third going to KK Birla's daughter Nandini Nopany, one-third to a trust managed by Nopany and her sister Jyotsna Poddar, and the remaining to RS Lodha, to whom Priyamvada Birla had bequeathed the assets.

The division may see the trusts going to one side and the businesses to the other.

Family members said KK Birla's daughters were being pitched as frontrunners for a major share of the property as Priyamvada Birla and her husband MP Birla were understood to be very close to them.

The sources said a mediator, probably a top lawyer, would soon be entrusted with the task of getting the parties agree to a settlement. The Lodhas were not available for comment. The sources said the proposal could be loaded in favour of the Birla  family.

In public, however, both have put up a brave front and are refusing to accept that any middle path is being discussed.

SK Birla, speaking on behalf of the family, said, "We are in favour of a reasonable settlement, but the other side is yet to furnish a copy of  the document. It appears that we will have to go to court even to obtain a copy of the document."

Yashovardhan Birla, the youngest in the family, today filed a caveat in the probate section of the district judges court here. Yashovardhan Birla is the grandson of MP Birla's brother Gajanan Birla and son of Ashok Vardhan Birla.

The caveat will ensure that Birlas are given an opportunity to present their views if RS Lodha  moves to probate it. Meanwhile, the Lodhas are likely to consult lawyers to discuss their gameplan.

Legal sources said the lawyers' team of the Birlas would be headed by former West Bengal Chief Minister and Punjab Governor Siddhartha Sankar Ray.

The lawyers representing the Lodhas are likely to be led by Samarditya Pal, husband of Justice Ruma Pal of the Supreme Court.

The MP Birla empire consists of nine companies, with the flagship being Birla Corporation. It also has healthcare facilities like Bombay Hospital and Belle Vue Clinic in Mumbai and Kolkata, respectively, and is planning to set up an MP Birla Eye Foundation. It also runs many education institutions around the country.