how to add multiple columns to a group by case?

I have the following group by clause on my query which uses a case statement yet I want to add another column to the group by too:

        group by case @dateTypeWHEN 'Daily' then i.overridedateWHEN 'Weekly' then dateadd(day,-1*datepart(weekday,i.overridedate)+1,i.overridedate) WHEN 'Monthly' THEN DATEADD(day, -1*DATEpart(day,i.overridedate)+1, i.overridedate) WHEN 'Quarterly' THEN dateadd(mm,-3,DATEADD(qq, DATEDIFF(qq,0,i.overridedate )+1, 0)) END

how do I add another column to this group by?

group by case @dateTypeWHEN 'Daily' then i.overridedateWHEN 'Weekly' then dateadd(day,-1*datepart(weekday,i.overridedate)+1,i.overridedate) WHEN 'Monthly' THEN DATEADD(day, -1*DATEpart(day,i.overridedate)+1, i.overridedate) WHEN 'Quarterly' THEN dateadd(mm,-3,DATEADD(qq, DATEDIFF(qq,0,i.overridedate )+1, 0)) END--Edited,col1,col2,etc..,coln