JSON API group and subgroup EmberJS

So I want to build the following select dropdown in ember, using ember data and the API is going to be using the JSON API spec. Here is a screenshot example

So would I in the services model, state the following

app/model/service.js

category: DS.belongsTo('category'),
subCategory: DS.belongsTo('sub-category')

app/model/category.js

service: DS.hasMany('service'),
subCategory: DS.belongsTo('category')

app/model/category.js

service: DS.hasMany('service'),
category: DS.belongsTo('sub-category')

I feel like I am missing something? Thoughts