Lookup combined with sum formula

Hi,

First of all I want to say thank you for a great forum. I have learned quite a bit in the last few days just by reading on here and imitating Formulas.

I am trying to do a simple lookup formula combined with SUM and need your help.

Please take a look at my attached Excel-file. I have one sheet called "Division" that lists three different groups. Each of the groups have a certain sheet.

In the B column in the Division 1 sheet I need a lookup formula that go to the correct sheet, get the values in B2 and C2 and sum them.

Appreciate your help.

Thanks.