Report builder - count grouped items

[Grantx]

In my report, each person is grouped because they could have more than one address.

How do I count the number of grouped results so that I can specify postcode1, postcode2, postcode3 etc...?

This is the report builder part:

This is the result when I run the report:

[d_gosbell · Accepted solution]

You can use the RowNumber() function passing in the name of the parent group. So if your group is called "Fullname" you could change the postcode to an expression like

= Fields!Postcode.Value & RowNumber("Fullname)