Two Sydney sisters, Julian Ambrose and Sam Buckeridge, children to their billionaire father Len Buckeridge, have filed a legal battle against their family to secure a $90 million fortune.

Sixteen-year-old Alba and the 19-year-old Stephen are beneficiaries of two discretionary trusts, the Buckeridge Family Testamentary and the Buckeridge Grandchildren Trust, which entitle them to 5.6 percent shares in the BGC Group, according to court documents. The BCG Group is one of Australia’s largest private companies.

SMH states that the teenage sisters are not seeking money from their father’s fortune, but are trying to establish “adequate provisions” in the will to ensure reasonable amount of share for themselves.

Len was a West Australian construction baron who died in 2014 at the age of 77, leaving behind a $2.5 billion estate. His massive wealth is the reason behind the growing family feud.

Another daughter of Mr. Buckeridge, Lise, has also joined the battle over her father’s fortune, which has sparked conflicts among 22 different parties that will settle for a mediation in July. The two siblings, Alba and Esperance, are pursuing studies and hobbies at the same time.

Based on the Facebook profile of Alba, she seems to have taken interest in her mother’s artistic passion. Other than that, her posts on social media reveal her inclination towards Australian landscapes, environmentalism and indigenous recognition. Esperane, who is three years older than Alba, recently attended the local public school Rose Bay Secondary College.

When approached by the Fairfax Media, the mother of the two sisters declined to comment regarding her daughters’ legal battle. “I have to ask my lawyers and protect the privacy of my daughters,” she said.

While the legal battle has taken a toll on its family members, Andrew Teo, the financial director and secretary of BCG Group, also had to launch a fight in the court to receive representation and confidential legal advice to administer five of the family’s trusts. However, two of the Buckeridge family members sought help in the court to exclude Teo, but their arguments were tagged “seriously flawed” by the judge.