Product 'Categories' for feature planning Merged

Our product is composed of functional areas/components like Pricing, Trading, Hedging, which are a natural fit for 'Categories' on the Ideas portal. However, in addition to using these categories to filter and report on Ideas, I'd also like these categories to automatically copy over to Features during the promotion process, so that they can continue to be used at the feature level for planning, filtering, and reporting.

One suggestion is to model this as Custom fields, however this would mean some duplication between the values of Categories, and permissible values of this custom field.