I have 4 columns. Need to do following:-

- sort by columns A, B, C in ascending order.
- subtotal on change of column C
- change subtotal text to "Subtotal for Sto XXX" where XXX is column C
- insert a line after each subtotal for easy reading
- insert grand total at end.

I think this may sound easy for most of you. But I'm novice. Plse help.
Thanks.