Nested Select Dropdowns (Ember)

I'd like to create a component for nested select dropdowns. I have a working version that generates the initial dropdowns, but it doesn't handle actions.

• Every option in every dropdown can have any number of child dropdowns.
• When a user changes a dropdown, the children of the "old" option need to be replaced with the children of the "new" option.

I created a git repo with my current static example: http://ift.tt/1TjTWOP

Thanks for any help!