What's the best way to create a structure of nested groups?

Let's assume that I'm in a group `A`. Now I want to create a structure:
```
A
-- B
---- C
```

Is there any function that makes this task easy? Or do I have to split the path and go group by group and create it?

That's what I managed to achieve so far:
```ruby
def add_group(project, group_path)
splitted_path = group_path.split("/")

for i in 1..(splitted_path.length - 2)
current_path = splitted_path[0..i].join("/")
new_group_path = current_path + "/" + splitted_path[i + 1]
parent_group = find_group_by_absolute_dir_path(project, current_path)

parent_group.new_group(splitted_path[i + 1], new_group_path) unless parent_group.nil?
end

project.save
end
```

Start by tracing the group methods used in the issue's add_group example, especially find_group_by_absolute_dir_path and new_group. Determine whether the existing API already supports creating A/B/C in one operation; done should be a clear supported approach for building the nested structure, with its behavior verified for the shown path.

Written by the indexing model from the issue text.