How to determine breadcrumbs for products with multiple categories?

[nickalev]

I have designed an e-commerce system whereby I have products which can belong to multiple categories. This works well for searching and browsing and allows users to find products more easily.However, I have also implemented breadcrumbs on the product page, and I don't know how to determine which category the product should be shown as being in, seeing as it could be any of the categories that the product is in. Ideally I would prefer not to just select a category randomly.Does anyone have any ideas? I would be grateful for only help!Thanks, Nico