List and subtotal selected items, then print separate item list
 

I have a list of 20 possible different clients each that will play an
advertisement spot with a rate, length and quantity. How would I go about
displaying a subtotal of each clients "playlist" inputed in separate rows and
then print out each a separate playlist (like a packing slip) for each client.

For example (A-client/station, B - length, C- rate, D- quantity
A B C D
99.5 :60 100 15
1010 :30 190 22
99.5 :30 10 39
89.5 :60 0 24
107.5 :30 200 12
740 :30 150 12
610 :30 200 12
89.5 :30 50 27
100.5 :60 120 8

So from this example I would need 6 subtotals all listed below in separate
rows. I have been able to get a subtotal when there is only one station but
having trouble making them list out separately and automatically showing only
the ones that have entries.

Then I need to be able to print out a separate invoice for each station. I
could have a worksheet for each station but hoping to have a way to print
them from one sheet. Each invoice needs to show each stations items.