concatenation - Excel Concatenate Rows

I have this excel worksheet

A          B          c   
foo1       joo1       loo1

foo1       joo2       loo2
foo2       joo3       loo3
foo2       joo4       loo4
foo2       joo5       loo5

Now I want this

A          B                  c   
foo1       joo1, joo2         loo1, loo2

foo2       joo3, joo4, joo5   loo3, loo4, loo5

How do I do this, preferably with GUI?

Answer

If you are willing to write a macro...

Click the first "foo1" cell and run this. It will join the foo1's then the foo2's until it hits a blank cell. If you've never written a macro before perhaps we can walk you thru it.

Sub JoinThem()
   ' Go until blank cell (first click at upper left of range)
   Do While ActiveCell.Value <> ""
      ' If this row macthes the next row
      If ActiveCell.Value = ActiveCell.Offset(1, 0).Value Then
         ' Join first column overwriting the values
         ActiveCell.Offset(0, 1) = ActiveCell.Offset(0, 1).Value & ", " & ActiveCell.Offset(1, 1).Value
         ' and Join the second column too
         ActiveCell.Offset(0, 2) = ActiveCell.Offset(0, 2).Value & ", " & ActiveCell.Offset(1, 2).Value
         ' Since we placed the data into one row get rid of the row

         ActiveCell.Offset(1, 0).EntireRow.Delete
      Else
         ' Next row does not match, move down one
         ActiveCell.Offset(1, 0).Select
      End If
   Loop 
End Sub