Hi YongOk Kim,
Recently I used the mendix tree view widget:
Here we can find mpk with some examples:
I used the MultilevelTreeView.
It gives us the possibility to have more than 3 levels using the same entity and to create that levels manually or arrange a system to do automatically.
Please let me know if you need further help and if this information was useful
Perhaps what you’re looking for is this widget https://marketplace.mendix.com/link/component/38862