title: crystal report sum group within another group
body: <p>I have tbInvoice with VESSEL, ETA, AMOUNT something like this:</p>
  <p><a href="https://i.stack.imgur.com/mWtzZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/mWtzZ.png" alt="enter image description here" /></a></p>
  <p>and in CR, i have group ETA under VESSEL like this :</p>
  <p><a href="https://i.stack.imgur.com/03eoO.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/03eoO.png" alt="enter image description here" /></a></p>
  <p>I have @total as formula in CR like this :</p>
  <p>Sum ({tbInvoice.AMOUNT}, {tbInvoice.VESSEL})</p>
  <p>and the result is like this :</p>
  <p><a href="https://i.stack.imgur.com/jGQ4e.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jGQ4e.png" alt="enter image description here" /></a></p>
  <p>What i want is result like this :</p>
  <p><a href="https://i.stack.imgur.com/ToWuf.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ToWuf.png" alt="enter image description here" /></a></p>
  <p>Which part i have to modify? Pls Help.
  Thanks.</p>