You can derive your BiWeekly incremented field value from week, maybe like
ceil(week(Date)/2) as BiWeek
but for some years, you will have an inconsistent BiWeekly increment at year's end (years with week number 53).
You can use something like
div(weekstart(Date),14) as BiWeek
to create a continuous Biweekly numbering across all years.
Hope this helps,