How to compare depend on only one field in each group?

Question

How to compare depend on only one field in each group  crystal report?

 

Group by Department 

 

Month  Dep         Salary              Allowance 

Nov     Admin     14 3,931,000   84,099,310

Dec     Admin     14 3,390,620   583,801

 

In the above report view, the report is group by department .

I want to highlight at only maximum Allowance field but not entire row in group in crystal report.

Please advice me

Thanks advance