You need to use the Constants function in CRD. To access these, right-click in the field you want to add a constant. Select "Insert". Select "Constants".
In your case I would insert the @@CRD constant of Key Parameter Value into the "Customize the output filename" field.
Now insted of your reports all being called the same thing an overwriting each other, they will be called different names. Assuming your key parameter values are your customer names, then the reports will be named after each customer.
You madame...are a genius. Thanks to both of you. I had tried a number of the constants/db fields with little success...but this one seems to work. Much appreciated.