Hi

No this is not possible, without writing VBA code to hide "sets" of Sheets
and unhide others.
You could label your sheets as A1, A2 ... B1 B2 etc.,
There is code available on Chip Pearson's site that will sort sheets in
alpha order for you.
http://www.cpearson.com/Excel/sortws.aspx

There are several add ins that have been written which allow you to have a
floating toolbar to enable sheet selection.
One such example would be Dave Peterson's, which can be found at.
http://www.contextures.com/xlToolbar01.html

or for XL2007 the code has been modified by Ron de Bruin
http://www.contextures.com/xlToolbar01b.html
--
Regards
Roger Govier

"Curious" wrote in message
...
I work with spreadsheets with many tabs, and it would be nice if I could
see
only groupings of tabs at the bottom...and then do something like double
click on a grouping to see all the tabs. Example: tabs a,b,c,...1,2,3...;
but on the bottom I would only see folder tabs "alphabet" and
"numbers"...and
then I could double click on one of them to see the sub-tabs. Is this
possible?