Go to Setup-> Fees-> Weekly and then select the "One Time Bowler Fees" tab (not the Last Weeks tab).
The second to the last column on the first line, change the "Y" to "N" and close the form.
This will make the Last Weeks fees optional but everyone on a team should be included already. You will just need to change the status of the bowlers that don't need to pay. To do that, go to the Weekly Fees screen and click on the "Other Fees" button. This will give you access to the field asking if each bowler "Will Pay Final Weeks" fee. Remove the "Y" from any that don't need to pay.