component.js

import Ember from 'ember';
import SmartViewMixin from 'client/mixins/smart-view-mixin';

export default Ember.Component.extend(SmartViewMixin.default, {
  router: Ember.inject.service('-routing'),
  store: Ember.inject.service(),
  actions: {
    selectTreatment(patientId) {
      const treatmentCollection = this.findCollectionByName('treatment');
      const treatmentCollectionId = treatmentCollection[0].get('id');

      this.get('router').transitionTo(
        'rendering.data.collection.list.viewEdit.summary.index', 
        [treatmentCollectionId, treatmentCollectionId, patientId]
      );
    }
  },

  findCollectionByName(collectionName) {
    const collections = this.get('store').peekAll('collection');
    return collections.filterBy('name', collectionName);
  }
});

template.hbs

{{#each records as |record|}}
  <div class="wrapper-card">
    <div class="card--title">
      <h2>{{record.forest-name}}</h2>
      <div class="summary-field patient-field">
        <label class="c-form__element">
          <strong class="c-form__label--read c-clr-1-2">Patient Count:</strong>
          <p class="c-clr-1-4">{{record.forest-patient_count}}</p>
        </label>
      </div>
      {{#each record.forest-patients as |patient|}}
        <li>
          <a href="#" {{action "selectTreatment" patient.id}}>{{patient.forest-name}}</a>
        </li>
      {{/each}}
    </div>
  </div>
{{/each}}