Dynamic Grouping in Report NAV 2009

I have a requirement of creating a report that groups the output , on the basis of the grouping option selected by the user. The report primarily has to group on bass of the following parameters: Customer,Salesperson Code,City,State (coming from Customer table) and Global Dimension 1 (i.e. Location) and Global Dimension 2 (i.e. Branch) (coming from the Location table). I had decided to initially test the grouping only on Customer fields. So this is how I did it:

Keys on Customer DataItem is set to Salesperson,City,State Code. and group total fields No.,Salesperson Code,City,State Code

Have made a separate GroupHeader for every grouping parameter. So in this there would be 4 GHs.

On every OnPresection written the following codes:

***** For Customer Grouping****
IF GroupBy = GroupBy::Customer THEN
BEGIN
Customer.SETCURRENTKEY("No.");
CurrReport.SHOWOUTPUT := CurrReport.TOTALSCAUSEDBY = Customer.FIELDNO(Customer."No.")
END
ELSE
CurrReport.SHOWOUTPUT := FALSE;

*******For Salesperson Code*********
IF GroupBy = GroupBy::Salesperson THEN
BEGIN
Customer.SETCURRENTKEY("Salesperson Code",City,"State Code");
CurrReport.SHOWOUTPUT := CurrReport.TOTALSCAUSEDBY = Customer.FIELDNO(Customer."Salesperson Code")
END
ELSE
CurrReport.SHOWOUTPUT := FALSE;


And so on for other parameters. Where GroupBy is an Option variable.
However, the Report output comes out blank.

Any suggestion would be highly appreciated.