Search files option - Adding a subset of drives as an option to search files

I'm running WXPSP3.
Under the Windows Explorer Search files option, I would like to add a subset of drives as an option to search for files.

I have Googled this but the results are ambiguous.
This has nothing to do with Windows Search indexing options.

Now that's it's common to have Terabytes of storage, I have many partitions on my drives. It simplifies defragmentation.

Many times when I'm searching for a file, I know it's not on drive C. But that's the first place Windows Search starts. Instead of searching all drives/partitions , I need an option to search a subset of all drives/partitions. Starting with drive D usually.
Where is the code that specifies these parameters? Registry? If so, what section.
I searched the Registry for "C:;D:;E:;" and found nothing. So it could be hard coded.

Thanks in advance.