Drop Downs and Computed Properties

I’m looking for some advice on what seems to be a trivial problem, but all efforts at googling for a best practice turned up zilch.

Throughout my application, I have drop downs (Ember Select views) that need to list all of a type of data, save one: Itself. I think it will make more sense if I explain with an example.

In my app, I have a model for Organizations, Orgs. An org can have a parent or a child org, but its parent or child org cannot be itself. When I prototyped the app, I hooked up the select to a property such as this:

organizations: function() {
 		return this.store.findAll('organization');
}.property('organizations').cacheable()

The issue is, what is the best practice if I want to, essentially, take this list and remove the model object from the list, before populating the dropdown?