I want to know if there is a way to set different expressions for the same variable but in different locations on a layout.

For example [zip] is in an address block should be = [zip] while onecode[zip] should be used just below the address block.

I have inserted two text variable boxes on my layout and embedded [zip] in both and have tried to set a different expression for both with no luck - if you change the [zip] expression in one text box it changes it automatically in the other text variable box.