Bill, you can group the same initial field multiple times.

If you initially group your dates into weeks this becomes Group 1 (which you
can rename to weeks) if you then Group this Group 1 (Weeks) into months then
you get Group 2 (which you can rename to months). You can then have one pivot
table showing the data by weeks and the other by months.

Alternatively, you can add an extra dummy column to the data for the second
pivot table that you create, and Excel will after a couple of actions treat
each table separately.

"billwoodard" wrote:

In Excel 2007 I have one data table, say Dates by Weight, and want to see and
save two pivot tables & charts, one grouped by weeks, the other by months. If
I simply change the date grouping in one table, the other table also changes.
I could create two separate data tables, but I'd like to be able to add new
data to only one table. How can I keep the groupings in the 2 pivot tables
distinct without losing the ability to update each of them when the main data
table is updated?

Thanks for any tips.