Right now, imports only allow mapping to main items, but it would be really helpful to have the ability to bulk upload subitems.
For example, if you have an Excel sheet where:
Item
Subitem
Color
Age
Dogs
Labrador
Yellow
3
Dogs
Pit Bull
Black
6
Cats
Tabby
Orange
5
Cats
Siamese
Cream
8
Birds
Parakeet
Green
1
Then it would map like the screenshot below: