Mr Baron insists he won a stake in the $50 million jackpot with a separate ticket he bought alongside the one he purchased for the syndicate, The Age reports.
He collected $20 from each of the syndicate members and entered the Powerball draw online via an online Tatts Group account - the group had entered the lottery regularly since 2009.
Mr Baron repeatedly denied winning the jackpot to his fellow syndicate members and allegedly told one he had received a significant sum of inheritance.
Fourteen members of the syndicate plan to challenge Mr Baron in the Supreme Court of Victoria where they will claim they have a right to an equal share of the winnings.
The $50 million jackpot drawn in October was won by Mr Baron as well as a Melbourne couple and a West Australian man.
The group of colleagues, who regularly bought Tattslotto tickets but only played Powerball when there was a major jackpot, want details of how many tickets the man bought and the method of payment.
It is anticipated Mr Baron will argue he bought the winning ticket separately to the group ticket.
The fifteenth member is reported to now be in a relationship with Mr Baron and no longer wants to be involved in the legal challenge.
A day after the draw in October Mr Baron, who was only referred to as a Victorian man, told Tattersalls he planned to share his fortune and wanted to remain anonymous.
"I'm still in disbelief... I don't need that amount of money, it's too much for me,' he said in a statement released by Tattersalls.
"I'm going to share the prize money with my family. I'll make sure it doesn't change who I am but I'll definitely be able to live a better lifestyle.
"I'll buy myself a boat and a jet ski and my kids have been wanting the new iPhone 6 so they can have that now, and I might spoil them each with a new car."
- Daily Mail