title: Creating multiple dataframes (2) based off value in one column and stop when another value is observed
body: <p>A dataframe structure looks like so:</p>
  
  <pre><code>Date   Amount1     Amount2     Amount3
  
  NaN     Port        NaN        thing1
  1/1/17     2         3           3
  2/1/17     2         3           3  
  2/1/17     2         3           3  
  4/1/17     2         3           3  
  5/1/17     2         3           3  
  6/1/17     2         3           3  
  7/1/17     2         3           3  
  8/1/17     2         3           3 
  9/1/17     2         3           3
  10/1/17    2         3           3
  11/1/17    2         3           3 
  12/1/17    2         3           3      
  NaN     Port        NaN        thing2
  1/1/17     2         3           3
  2/1/17     2         3           3  
  2/1/17     2         3           3  
  4/1/17     2         3           3  
  5/1/17     2         3           3  
  6/1/17     2         3           3  
  7/1/17     2         3           3  
  8/1/17     2         3           3 
  9/1/17     2         3           3
  10/1/17    2         3           3
  11/1/17    2         3           3 
  12/1/17    2         3           3  
  Total     Nan        NaN        NaN
  1/1/17     2         3           3
  2/1/17     2         3           3  
  2/1/17     2         3           3  
  4/1/17     2         3           3  
  5/1/17     2         3           3  
  6/1/17     2         3           3  
  7/1/17     2         3           3  
  8/1/17     2         3           3 
  9/1/17     2         3           3
  10/1/17    2         3           3
  11/1/17    2         3           3 
  12/1/17    2         3           3  
  NaN        Nan       Nan         Nan
  </code></pre>
  
  <p>I am interested in creating 2 dataframes.</p>
  
  <p>1.One dataframe collects the rows after thing2 is observed in the amount3 column and stops the row before total is observed in the date column.</p>
  
  <p>2.The 2nd dataframe will start on the row after total is observed and stop when a NaN (null) value is observed. </p>