allocate shipping and handling to varying number of items in an or
 

I receive a spreadsheet which shows the following type of sales information
(its wrapped-copy and paste to excel for review). Basically the shipping and
handling per order is summarized below each order. Each order can have
varying number products in it, one item per line. Is there any easy way to
allocate the shipping to each item within the order? So the formula will a)
recognize how many lines to divide by, i.e., stops at the previous "Shipping"
line and counts the number lines between each Shipping line and use that
number to divide the shipping charge and then populate it on each line?
Thank you.
DESCRIPTION QTY UNIT$ EXT$ SHIPPING DISCOUNT GIFT CERT TAX TOTAL
The Book 1 1 $29.99 $29.99 $0.00 $0.00 $0.00 $0.00 $29.99
The Book 2 1 $29.99 $29.99 $0.00 $0.00 $0.00 $0.00 $29.99
The Book 3 1 $49.99 $49.99 $0.00 $0.00 $0.00 $0.00 $49.99
Shipping and Handling 1 $13.95 $0.00 $13.95 $0.00 $0.00 $0.00 $13.95