title: How to lock cells
body: <p>say i have 7 groups of 2 columns (14 columns in total) &amp; many rows like "ab" "cd" "ef" ect... but i want to lock one the cells in that column say "a1" has a value  then "b1" should be lock or if "b1" has a value then "a1" should be lock automatic like the otherones "cd" "ef" ... But not to change any other cells only the ones in their group ab cd ef ect.. </p>
  
  <p>more exp:: if c20 have a value or number then d20 should be lock </p>
  
  <p>my sheet is base on profit or lose so i dont want 1 profit or 1 lose to be entered in the same group "ab" "cd" "ef"</p>