includes the commission of two or more criminal offences referred to in Schedule 1: Provided that at least one of those offences occurred after the date of commencement of Chapter 4 and the last of those offences occurred within three years after a prior offence and the offences were committed--
| a) | on separate occasions; or |
| b) | on the same occasion, by two or more persons who are members of, or belong to, the same criminal gang. |