Using Outlook 2000 - Internet Mail

I have all of my contacts divided into 5 different folders
under Outlook Today - these are primary contact folders
and not subfolders of the standard Outlook "contacts"
folder.

Question:

When I create a new mail message, and I click "TO" in the
address bar, how do I change the default setting for the
contact folder for address book? How can i set one of my
five folders to be the default as opposed to the Outlook
standard "contacts" folder being the default?

Any information would be greatly appreciated!  :-)
Thanks
KJ