I have a Pivot Field and it has Column1 , Column2,
Column3,...................,Coulmn10 in columns.

My requirement is that I want to label / group
Column1-Colun5   as Column One
Column6-Colun8   as Column Two
Column9-Colun10  as Column Three

I want to do it so that once users select / unselect various fields
they should be aware of which group are they of?
Also these groups should intelligently collapse or expand when the
users bring down the page fields down in row field

Could any one please suggest any answer?I will really appreciate.