Mongodb aggregate $push with $cond and $each
<p>I'm trying to use <code>$cond</code> to conditionally <code>$push</code> multiple integers onto a numbers array during an aggregate <code>$group</code> without any success. Here is my code:</p>

<pre><code>Item.aggregate(
    [
      {
        $group: {
          _id: "$_id",
          numbers: {
            $push: {
              $cond: { 
                if: { $gt: [ "$price.percent", 70 ] }, 
                then: { $each: [10,25,50,70] },
                else: null,
              }
            }
          }
        }
      },
    ]
  )
  ...
</code></pre>

<p>Is Mongo DB just not set up for this right now, or am I looking at this all wrong?</p>