is it possible to write a FormatString that only puts a whitespace in case the next field is not empty ?

My FormatString looks like this:

{1} {2}, {5}-{3} {4}

1= Adressfield1, 2=Adressfield2, 5=CountryShortcut, 3=postal code, 4=city

however, the field Adressfield2 may or may not have a value, and thus if it doesnt have a value,

the whitespace infront of it needs to go.

any ideas ?

thanks.