Macro To Create New Tabs Based On A Contract Number

I work with contracts and have to report the sales for each contract by customer number, name, address, product code or sku, sales amount, quantity, and invoice date. Each contract number is associated with a product group and within that product group are a laundry list of product codes or skus.

Customers are often on different contracts for different products and may purchase some or all of the products on that contract. When I run a query from the system to extract this data, I get one sheet that contains 20,000 lines that have to then be sorted and seperated into different tabs based on the contract number. Keep in mind that a customer may be listed multiple times because each line in the query represents a product code and an invoice date.

I currently have a macro that will format the reporting such that it sorts the data, however, what it doesnt do is look for each instance of a particular contract number and separate it into different tabs.

So below are two examples: April and May 2008 Reports

April 2008 Report
Contract 1 contains 5,000 lines of data - extract into new tab
Contract 2 contains 5,000 lines of data - extract into new tab
Contract 3 contains 5,000 lines of data - extract into new tab
Contract 4 contains 5,000 lines of data - extract into new tab
Total lines = 20,000

May 2008 Report
Contract 1 contains 7,500 lines of data - extract into new tab
Contract 2 contains 5,500 lines of data - extract into new tab
Contract 3 contains 8,000 lines of data - extract into new tab
Contract 4 contains 9,000 lines of data - extract into new tab
Total lines = 30,000

So for the April Example, I would like excel to take this one list and break into 4 new tabs based on the contract number and carry over all of the data into that tab.

Where this may become difficult is that there may be more lines of data one month and fewer another. Im not sure if there is a function that will tell excel to stop when it reaches the last line for one contract number and to start a new tab for the next contract number. (see the month of May example)