Using old mix of Roman, Arabic, letters, for rows

If I want this sort of numbering
I Vertebrates
A. Mammals
1. Carnivores
a. Canids
i. Canis lupus lupus

Do I have to do it in the Inspector, row by row? That’s 5 steps for getting the format above.

Applying a numbering format to the entire document results in, e.g.,

I Vertebrates
I. Mammals
I. Carnivores
I. Canids
I. Canis lupus lupus