Need Excel to automatically select correct columns to sum their values by currency

Hi there,
I have the following problem.
On tab 1 I have weekly sales numbers for different items which are sold in different currencies

Tab1----------------------------col A------------col B------------col C
-------------Week number---------2---------------3----------------4
1 Oranges (sales in USD)--------1,300USD-------2,660USD--------3,980USD
2 Apples (sales in EUR)----------1,000EUR-------2,000EUR--------3,000EUR
3 Pears (sales in JPY)-----------11,800JPY------23,650JPY-------35,700JPY

On tab 2 I need to re-calculate all sales numbers from tab 1 into one common currency (EUR) and to sum them to one number

Tab 2-----------FX EUR/USD------1.3-------------1.33----------1.327
-----------------FX EUR/JPY------11.8-----------11.825---------11.9

---------------------------------col A-----------col B-----------col C
----------Week number-------------2--------------3---------------4
1 Total sales in EUR per week----3,000EUR-------6,000EUR-------9,000EUR

Using sumif() function is possible but not a good solution as I have to manually select the columns to be summed. Does anyone see a way how to make Excel to automatically select the right column on tab 1 and to culculate the totals for the weekly sales?
Thanks