eBay Link and Omnivore only supports mapping to one eBay category as eBay strongly encourage you to list your item in the single most relevant category rather than multiple categories. This is to ensure that the most accurate and helpful search results are returned in buyers’ searches and in most cases you would be charged for listing 1 product in multiple categories.

Note: From 4 April 2018, when you list an item in two or more eBay categories and there is a difference in final value fees between the categories, the highest final value fee will apply when your item sells.