So i have a set of data with the same reference number but different dates:

e.g.
Record 1: Reference Number: 10000     Date: 20/12/2012
Record 2: Reference Number: 10000     Date: 21/12/2012
Record 3: Reference Number: 10001     Date: 19/12/2012

I want my report to display the first record if there are multiple records with the same reference number but sort the records by date.

I.e:
Reference Number: 10001           Date: 19/12/2012
Reference Number: 10000           Date: 20/12/2012

(It should not show record number 2 because it has the same reference number as record 1 and it should put record 3 above record 1 as its sorted by date).

So I've added a grouping by reference number and put what I want to display in the group header but I can't get it to sort by date this way. If I put things in the details line and add sorting by date, it works but then displays all records even those with the same reference number.

How can i get it to display what I want?

Thanks!