2 dependent drop-down menus sreference same drop-down

I would like to create dynamic drop-down menus where B2 & B3's selections are both dependent upon A2 - instead of cascading.

I found a Youtube video, and it worked...but it broke Excel, badly. Any time after it was done, I could no longer add rows to the table. And Excel would crash if I tried.

So for example, B2 is dependent upon what the user selects in A2. But C2 is also dependent upon what the user selects in A2.