title: Limit cell value input based on other cells selection
body: <p>I have 10 rows where the same column in each row has a "Data Validation" applied to with a list of "Important" and "Not Important". I want the user to select the value for this list based column for at the maximum 5 rows. Thus if he/she has selected "Important" in 5 rows for this column, then he/she should not be able to select value for this column in any more rows.</p>
  
  <p>How should this be achieved in excel.</p>