title: Eloquent/Laravel: Nested lazy eager loading, but return multiple model's relations
body: <p>Apologies if the title does not make much sense, but here's what I've got and what I'd like to achieve.</p>
  
  <p>There's a restaurant's menu, which is structured like this:</p>
  
  <pre><code>Restaurant
  |- category 1
     |- subcategory 1
     |- subcategory 2
        |- item 1
           * price levels:
           |- price level 1
           |- price level 2
           * modifiers groups:
           |- group 1
              |- modifier 1
              |- modifier 2
  </code></pre>
  
  <p>The goal is to write the most efficient way (in terms of database queries) to get the entire menu (served as JSON via API), but there's a catch: I need both price levels AND modifiers for each item.</p>
  
  <p>The most efficient way that I came up with is:</p>
  
  <p>Part 1: chain all the way up to item's modifiers (because they're more nested than price levels):</p>
  
  <pre><code>$this-&gt;restaurant-&gt;load('categories.subcategories.items.modifier_groups_enabled.modifiers_enabled');
  </code></pre>
  
  <p>Part 2:
  Before starting the loop through categories/subcategories/items, I "manually" get all price levels that belong to all items in a restaurant, then I put them into an array, grouped by item's id. Then, while looping through the menu, I just grab the <code>$price_levels[$item-&gt;id]</code> as an array of item's price levels.</p>
  
  <p>With nothing cached, the entire request is complete in 7 queries, which is OK, but the 'dirty' way of preparing price levels is bothering me a bit :) </p>
  
  <p>If I cut the nested eager loading up to items only, then get each item's price levels and modifiers (<code>$item-&gt;load[...]</code>), database queries pile up since each item runs its own ones to get price levels and modifier groups/modifiers.</p>
  
  <p>So, the question is: Can <code>$this-&gt;restaurant-&gt;load('...')</code> be written in such a way that it also returns all items' price levels AND modifiers?</p>