Grouping sheets and "closing" them.

I have a sheet for each month of the year. I was wondering if there was a way to group all sheets for all months of a particular year and "minimize" the sheets so I only have one tab but within it exists each sheet? Similar to outline but with sheets instead of rows.

Any suggestions?

a long winded way, is to hide all sheets except say 2007 sheets, then create a custom view for it, repeat for each year, then to switch beween years use its relevent custom view,

you could always save a custom view showing them all!