Lookup values in one spreadsheet and automatically input into another spreadsheet

I process airtime for telephone usage (individual calls placed to/from the phone) in a spreadsheet using multiple formulas to do so. Once completed, everything is sorted and subtotaled by "Customer Code", then "Date" then "Time".

I have one customer with 100 different "Customer Codes" and I have to manually copy the subtotal for each "Customer Code" from this spreadsheet into another spreadsheet that is a summary for the customer.

Is there an easy way for me to input a formula so that this information is automatically inputted into the 2nd spreadsheet?

The first spreadsheet totals change monthly.

FYI - these spreadsheets are in different workbooks...

Thanks in advance!

-Prefcomm