In WordPress we can create a post type which can contain taxonomies (or custom fields). Can these taxonomies (or custom fields) contain anything? For example other taxonomies or something else?

If I need a WordPress model where I’ve got people who have got pets who have got toys which have got colours… As you can imagine, two different people can have a cat; a toy for a cat can be at the same time a toy for a dog; the black colour can be a feature of many different toys. All the relationships are “many to many”. Is there a simple way of nesting these seperate data types respectively?