Find last but one element in #each helper in ember

In my ember application I've a scenario where I want to display the last but one element of an array in a different way.

{{#each item in model}}
   {{#if lastButOneItem}}
      + {{item}}
   {{else}}
      {{item}} +
   {{/if}}
{{/each}}

But I'm not sure how to put the condition for the lastButOneItem. Is there a simple way to achieve it ?

I tried assigning an ItemController for this. But I can't get the total number of elements from that item controller and the current index.

Any help please.