Understand loading of unrelated models for nested route in Ember

My routes look roughly like this:

```

/
  /sites
    /:site_id
      /settings
        /user-defined-params
          /:param_id  

```

Now in /user-defined-params I want to display table-list of parameters assigned to that given site. The models are not related, I mean site doesn't have collection of params as a relation, so I can't simply fetch them via this relation.

Should model() hook for my router return list of these params? By default the model seems to be site loaded from parent route (:site_id). What if loading takes some time and I'd like to actually display this table (so do actual transition) but then show kind of loading indicator waiting for table to fill in with the data.

When I try to load this in model() hook, transition blocks. When I try to load it in afterModel() hook, I don't have a way to assign it and make it available for template (other than force-assigning params property to site model, which seems to be wrong).

All the examples I've found over the Internet seem to be lacking this scenario, which I feel is one of the basic ones, so any hints on that? How should I load it (ideally without blocking transition)?