I have a workbook with the following two worksheets and columns:

Sheet1 and Sheet2
Column A = Program ID
Column B = Project ID

Sheet1 contains over 8,000 rows of pre-populated data and is hidden. For
each program, there can be one or more associated projects. This means that
if Program ID 1234 has three associated projects, then Program ID 1234 will
exist on three separate rows. Sheet2 contains no data.

On Sheet2, I would like to add data validation dropdown list boxes in column
A, and dependent data validation dropdown list boxes in column B. The source
of data for the data validation dropdown list boxes on Sheet2 would obviously
be from Sheet1.

(Note: for those programs that have more than one associated project, I
would like the Program ID to appear only once in the data validation dropdown
list box in column A.)

I have already looked at the solution posted on Debra Dalgleishs website
(http://www.contextures.com/xlDataVal02.html), but given the number of rows
of data on Sheet1, using her solution would not be practical.

I would greatly appreciate any help in coming up with an alternative solution.

Thanks,
Bob