title: Filter one sheet by a range in another sheet
body: <p>I have a Google Spreadsheet document that I'm using to maintain a reference of all business logic on various systems.  It is comprised of 2 sheets:</p>
  
  <ul>
  <li>Sheet1 is a view of all of the logic.  Each row has a unique <code>code</code> column (column B) and many details about the logic being done in other columns</li>
  <li>Sheet2 is a mapping of the systems to the logic.  Each system is on one row.  From column E onward, each cell is exactly a <code>code</code> from Sheet1</li>
  </ul>
  
  <p>The relationship between <code>code</code> and system is many to many, so the same <code>code</code> may be used by many systems, and each system may have many <code>code</code>s.</p>
  
  <p>I would like to be able to filter Sheet1 based on whether the <code>code</code> column in each row is found for particular systems.</p>
  
  <p><strong>Example</strong></p>
  
  <ul>
  <li>System A and System B are in Sheet2 rows 50 and 51</li>
  <li>Their codes are from column E to K</li>
  <li>Filter Sheet1 by <code>code</code> where <code>code</code> is contained in Sheet2!E50:K51.  The end result should be Sheet1 shows only those codes (and of course all columns for them)</li>
  </ul>
  
  <p>I have seen and tried a bit of the usual suspects (ARRAY_FORMULA, INDEX, LOOKUP) but I do not yet grok them fully.  I thought the answer would be going to "Filter -> By Condition -> Custom Formula is" but I'm not sure what to put there.</p>
  
  <p>Any help is greatly appreciated!</p>