Merging Table Cells With Text Under Certain Conditions

From a supplier I will get a spreadsheet including the the following Information which I need to convert into an url including trailing slash (/) for an online store.

Column A = Value of Main Cartegory (e.g. Holidays)
Column B = Value of Subcategory_1 (e.g. Christmas Decor)
Column C = Value of Subcategory_2 (e.g. Candle Holders)

Those raw data are without any trailing slashes.
Now I want to create a column e.g. Column D (product_url) which should be a summary of column A thru C but if there is only a Value for Main Category
there should be no trailing slash,
if there is a Value for Main Category and a Value for Subcategory_1: no trailing slash after Subcategory_1 but trailing slash between Main Category and Subcategory_1.

The result should look like this:
Holidays (Main category)
Holidays/Christmas Decor (Main category & Subcategory_1)
Holidays/Christmas Decor/Candleholders (Main category & Subcategory_1 & Subcategory_2)

Is it possible to create something like that in Excel at all since all values will only be text and the trailing slash is actually functional for Excel calculations but in this case it would have to be treated as "text".