Creating A Grandtotal From From Subtotals

Can someone tell me how to get a grand total ? I have a Crystal Reports that use formulas to create subtoals for each individuals. I have successfuully created the subtotals, but can't figure out how to get the grandtotal.

When I look in 'Insert Summary') '@Totals' is not listed. I also tried to summurize the formula (using 'Sum'), but I get an error stating ('This field cannot be summurized'). It appears that Crystal Reports can't summurize a formula that has 'Sum' within it. Is this correct ? I see the correct figures on the Crystal Reports that are calculated by the formula, but can't get a grand total. What is an easy way around this ? Below is a flow of the formulas. Thanks ! ! !

@Totals (Formula) - Totals individuals overall figures
-- @SumA (Formula) - Calculates subtotals for each individual
----- @SumB (Formula) - If statement for each individual to calculate subtotals correctly (this
---- formula use'Sum')
------- @SumC (Formula) - Calculates commissions (calls @SumD)
------------ @SumD (Formula) - Calculates special situations (use WhileReadingRecords)
----- @SumE (Formula) - Retrieve ovveride figures

Create a shared variable to store the total of the first indvidual and keep on adding the total of the next indviduals in it.