Scope select options to a particular resource?

[wengzilla]

I would like to scope a BelongsTo field to a particular set of things based on the resource, but I'm not sure how to achieve this...

Right now, I have the following relationship: Companies have many Departments which have many Employees. Or, in other words, Employee belongs to a Department which belongs to a Company.

I want to have a field on my EmployeeDashboard that looks as follows:

ATTRIBUTE_TYPES = {
    departments:
      Field::BelongsTo.with_options(scope: ->(resource) { resource.company.departments }),
  }.freeze

I could monkey patch the scope call to pass in resource, but is there a more elegant way to do this?