Okay. Are the calculations something you could do in custom Transaction Body or Line fields? That will work, because you can set the field type to Currency and they will automatically render in the correct formatting with the correct currency symbol. If not, then the solution could be complex. You could grab the first character of any currency string (assuming all of your currencies render with the symbol at the beginning) then use a number format, such as

?string[",##0.00"]

or

?string[".##0,00"]