Sure! The formula converts the US week number to an EU week number. WEEKNUM(Date) returns the US week number; at the time of this writing, it will return 8, and this coming Sunday, it will return 9. The latter is an incorrect EU week number, since th...

It’s a bit of a hack, but for my purposes, the following simple formula has been useful for grouping: WEEKNUM(Date) - IF(WEEKDAY(Date) = 0, 1, 0)