Adds all variables within a category that match the given name.
VariableSum( [Category Path], [Variable Filter] )
Category Path is the path to the category whose variables will be processed, nested categories can be separated with the backslash.
Variable Filter is a string which will be used to match variables.
|VariableSum("Quote\LineItem","* TotalPrice")||Will add all variables, in the Quote\LineItem category, ending in TotalPrice|