Crystal Reports display subreport values based on Parameter ?

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Hello,     I am new to crystal reports any help will be appreciated.

I am having a main report which contains Expenses data grouped by department,program.
The data is like
                                     LastYear     PresentYear
 cd                                   10                20
    cdxm01                          5                   8
    cdxm02                          5                  12
  sus                                 40                60
    susab01                         10                20
    susab02                         30                40

I have the Subreport which contains Revenue .Data is grouped by object code,program.The data is like

Object code                         Last Year           Present Year
  4100                                    30                         15
      cdxm01                             10                          5
      susab01                             20                        10    

 4200                                     30                          70
      cdxm02                            20                          40
      susab02                            10                         30.

they are two parameters  department and program.They can allow multiple values.So when the user enters two values the output should be like

    Cd
                                         LastYear     PresentYear cd                                                                          10                               20
    cdxm01                                                         5                                   8
    cdxm02                                                           5                                 12
     Total department Expense   10                20

                                        LastYear            PresenetYear
 4100                                    10                    5
    cdxm01                              10                    5
 4200                                    20                  40
     cdxm02                             20                  40
      Total Revenue                  30                   45
     Over/under                        -20                -25.
In a similar way it should display for all the departments.I linked the subreport with department parameter with department field in subreport and program paramter also.

When the user selects One department it is working but when i select more than one department it displays the expenses correctly but it displays revenue values silmilar for all the departments.
Is there any way to do this ?any help will be appreciated.
FYI i have placed the subreport in the department group footer.