How to assign TestNG test results to use cases?

I need to assign my test results to use cases. Currently I have TestNG tests for my classes (unit tests). Obviously those tests are classes exist because of use cases, but there is no obvious 1-1 mapping.

Is it possible to configure TestNG reports to include custom groups in reporting?

Like

F02UC01 parse input for this use case I have test classes:

• com.company.product.input.ParseTest

F03UC02 produce output for this use case I have test

• com.company.product.input.OutputTest com.company.product.input.AnotherOutputTest

Ideally, I do not want to rerun or rewrite existing tests. I just want another test report, with diffrent grouping criterias.