I'd like to set up collections of products. My client sells handwoven goods. I'd like to be able to put all the matching "southwestern" products in a collection and all the "Corn Goddess" products in another. Because the product are diverse, (a purse, a rug, a tote, a duffel bag, etc) they are in different categories. I think the best way to set this up is to make a read-only "Collection" attribute and show all products that have said attribute. Is it possible to list items with a specific attribute?