How do I remove repeating rows in SSRS Report

SSRS report has a 'textbox' with expression(shown below) inside the report body and inside a 'List'. Note that the fields are not part of any tables. These values are hardcoded in the expression.

=IIF(Fields!contact_list.Value="25",(IIF(Fields!Category.Value="college","Two-year Colleges", "System") ),IIF(Fields!contact_list.Value="71","System Continuing Offices",(IIF(Fields!contact_list.Value="51","Free Colleges and Universities", "Unknown Pool"))))

I need to remove the repeating rows which is coming from the above expression. Example: Currently, 

**System**
    Sub Header 1
    Name1
    Phone1

**System**
    Sub Header 2
    Name2
    Phone2

**System**
    Sub Header 3
    Name3
    Phone3

**Two-year Colleges**
    Sub Header 7
    Name7
    Phone7

**Two-year Colleges**
    Sub Header 8
    Name8
    Phone8

Expected result:

 **System**
    Sub Header 1
    Name1
    Phone1

    Sub Header 2
    Name2
    Phone2

    Sub Header 3
    Name3
    Phone3

**Two-year Colleges**
    Sub Header 7
    Name7
    Phone7

    Sub Header 8
    Name8
    Phone8

How do I avoid not displaying the repeated rows?? Any help would be appreciated. Thanks in advance.