Multiple selection on pyvot table.
 

It is kinda tricky to make a multiple pivot table, but I found out. By the
way ribbon are great but are not showing all the possibilities of excel 2007.

In excel presse F1.
Make a search on Consolidate multiple worksheets into one PivotTable report
Then choose Consolidate data without using page fields

You will discover then that you can acess a PivotTable and PivotChart
Wizard, press ALT+D+P.

Good luck.