The crown alleged McAllister had been lured to Stadium Southland by Laura Scheepers, with the promise of sex, to lull him into a false sense of security, who then relayed where she was to defendant Christopher Brown.
The other defendants, along with Whiting-Roff, arrived at Stadium Southland, where the assault took place, Donnelly said.
He said there was "significant animosity" towards McAllister by a number of individuals in the group, based on a belief McAllister had acted "inappropriately" towards girls.
Donnelly said evidence would show the defendants had a shared understanding of the elements involved leading up to the incident, and each knew the probable consequences of their assistance.
Members of the jury were shown CCTV footage of the incident at Stadium Southland, including a moment the crown alleges was Whiting-Roff stabbing McAllister.
Because of the number of defendants and security required, family members and the general public will view the trial from a separate court room.
Justice Rachel Dunningham told the court the jury empanelling was the longest she had seen by far.
Forty-six potential jurors were excused, and another 19 were challenged by the defence or crown before the jury of seven women and five men were selected.
The trial is expected to run for five weeks.