@chhonmeily, I would keep it as simple as you can. First off, it's ui-select. Create your two inputs using the ui-select library, then in the first edited input, add a ng-change which triggers a scope function that would then filter the second input. Set the second repeat to that filtered list. You could even disable the box until the user selects the first one. PM me if you want to send me an example, or have other questions.