Sections under sections

Hi,

I have 9 section components spread across 3 rows and displayed in 3 adjacent columns.

Something like:

section1 | section2 | section3

section4 | section5 | section6

section7 | section8 | section9

All three are collapsible. Now, the user has to open each section one-by-one to view the data under the respective section.

Is there a way I can place each row under one main section and make only the main section collapsible so that the user has to only click once to see the sub-sections?

SectionA (collapsible)

section1 | section2 | section3

SectionB (collapsible)

section4 | section5 | section6

Please feel free to suggest alternatives (if any) to suffice this requirement.

Regards,

Sunil Zacharia