Adding Subcategory of "WST" or "Water, Sewer, Trash" under the "Utilities" category

Hello, I was wondering if you’d be able to add an expense sub-category called “WST” or “Water, Sewer, Trash” under the category of “Utilities”. Many of the cities bill for all 3 utilities in one bill. I’ll continue to choose the category of “Water & Sewer” but it isn’t completely accurate for my record keeping