Adding custom top-level category to multiple hierarchy manually

Hello

In my XML feed I have element named “categories” that “contains the entire multiple hierarchy”, like: “cat > sub cat > sub sub cat | cat1 > sub cat1 > sub sub cat1”

I tried to add custom category like this: “Top-level category
> {categories[1]}”, but it didn’t create categories hierarchy like

Top-level category
-cat
–sub cat
—sub sub cat
Top-level category
-cat1
–sub cat1
—sub sub cat1

its only work for the first hierarchy and create categories hierarchy like this:

Top-level category
-cat
–sub cat
—sub sub cat

cat1
-sub cat1
–sub sub cat1

Please, is there any option how to do it correctly, or any alternative solution to import items to previously created top-level category?

Thanks a lot for help!