Here is the macro:
ActiveCell.Value = ActiveCell.Offset(-4, 0).Value & "-" & ActiveCell.Offset(-3, 0).Value & "-" & ActiveCell.Offset(-2, 0).Value & "-" & ActiveCell.Offset(-1, 0).Value & "-" & ActiveCell.Offset.Value
You can assign a <function key> if you like by pressing Alt+F8 and selecting options (bottom right of the window).
You will still need to select all the destination cells manually and run the macro after each one, but it goes a lot faster then the previously provided function.
The best way I found for doing this is to select all the destination cells and use ENTER to toggle between them. So select cells, run macro (using function key), hit enter, run macro, enter, macro, enter .... etc..
Unfortunately my limited VB knowledge doesn't allow me to write a code where you will only need to run the macro once after selecting all the destination cells.