Summarizing Scattered Data

I have a worksheet filled with invoices... I want to summarize the data in another worksheet. I can do it manually for one party, but as i have to do it again for many parties with different data, it will be toilsome for me.

I have attached the worksheet with invoices and the worksheet with the summary. I have summarized the invoices manually. I want a formula or something so that I can summarize the data of other parties automatically when I copy the summary sheet's links and paste it on other parties' excel file, so that it will automatically deduce the summary from the invoices of the relevant party.