Newbie question.

Working in Excel 2000.
I have a workbook with a range called 'ABC'. I reference this range within a
VBA function as:
x = Application.Range("ABC")
This works well as long as it is the active workbook, when switching to
another workbook and forcing a calculation the range is not found. The way
to do this of course is to qualify it as:
x = Application.Range("'[Workbook.xls]Sheet1'!ABC")
Great, my problem is that I am not doing it in VBA but via a COM interface
where I only have the range name, not the workbook, or the sheet name!

My question: Is it not possible when defining a Range to include the
Workbook qualification in some way? When I try to do this via the menu
system, Excel just 'loses' this extra information?

Any help appreciated!