Conditional formatting of the group depends on a field of all associated lines

Hello,
I wantagroupfieldasredrepresent,ifincluded inaparticulartext boxthe valueDL*.

Example of the Dataset:

Productname | Price | Text
A                  | 01    | ABC
A                  | 02    | DL-123

Now, the Field Productname should be RED in the Group Row.
If tried with: =iif(Fields!SalesLine.Text.Value like "DL*","RED","BLACK")
but this only worksifthefirstdetaillinecontainsthe valueABC in the TextBox TEXT.How can i solve this Problem. thanks