Using Cycle Group as <Group> in sum(Total <Group> Field) function

[#1]

sum( {1< Manufacturer = >}Total <[Calendar Year]> [Total Sales])

How do I get the above formula to change based on the field in the Cycle Group?  The below wont work.

sum( {1< Manufacturer = >}Total <GetCurrentField(InvCycDate)> [Total Sales])

[#2]

try [cyclegroup] as:

sum( {1< Manufacturer = >}Total <[GetCurrentField(InvCycDate)]> [Total Sales])