[ic] Putting non-products into a Cart -- is this possible?

[fallen at specialty-books.com]

Hello.  We have a number of catalogs, and want all of them to share a
certain system.  This system will allow users to search a global database,
and if they desire, to place items from that database in a seperate cart
from the main cart, and process them through a special order process.
I have played with it a bit, and am getting few results, mainly around the
action of getting one of the items from the global DB to go into the cart.
Is this possible?  Does the global database need to mimick the product
databases of the catalogs for this to work?
I'd love any help or advice,
Thanks,
Andrew