I think we are talking past one another. What exactly do you mean by "manual process only." I have explained (briefly) how to create a calendar and use the recurring exceptions to mark every other Saturday off which will not require you to manually change every Saturday. For step by step:
- Create a new calendar in Project 2007.
- In the Change Working Time dialog, click the Work Weeks tab, select the [Default] entry and click the Details button to open the Details for [Default] dialog.
- Select Saturday from the Select days list.
- Click the button next to Set day(s) to these specific working times:
- Enter the working times for Saturdays.
- Click OK to close the Details for [Default] dialog.
At this point you now have a calendar with every Saturday as working. Now you need to create a recurring Exception to mark every other Saturday off.
- Still in the Change Working Time dialog with the custom calendar open, click the Exceptions tab.
- Select the first Saturday in June - June 7
- Click in the first empty row on the Exceptions tab and name the Exception "Alternate Saturday".
- Click in the Start field to populate the start and finish with June 7, 2014.
- Click the Details button to open the Details for "Alternate Saturday" dialog.
- Under Recurrence pattern select Weekly.
- Select Recur every 2 weeks on Saturday.
- Set your range of recurrence as needed.
- Click OK to close the Details dialog and return to Change working time.
You now have a calendar where every other week has a working Saturday. You may now copy this calendar to the Organizer to make it available in all new projects.