Ah! I wondered if it would be specified as "party to the offence".
Curious they charged Macleod with both straight sex assault, and party to the offence of sex assault. Unless if there were two women involved he'd only ever get convicted of one or the other, but laying charges "in the alternative" can certainly happen.
Based on my understanding of the allegations, he both sexually assaulted her himself, and then aided / abetted the others in sexually assaulting her.
I would presume that those are separate charges and separate offenses, no?