Concatenate dates per week

[omega1983]

cast([MinLockExpirationDate],varchar(20))+'-'+cast([MaxLockExpirationDate],varchar(20))
This formula will give the min and max date for the entire report.  Is there a way to accomplish this and segment by a week
For example  minimum([LOCK EXPIRATION DATE] for Report) and maximum([LOCK EXPIRATION DATE] for Report) provide me the beginning and ending dates for the entire report and not segmenting by say a 1 week period.

The entire date range is between _add_days(current_date,1) and _add_days(current_date,60)  however I want the concatenate to show per week
2016-06-06 -  2016-0610
etc
2016-08-01 - 2016-08-05

Instead I am getting
2016-06-06 - 2016-08-05