Against a particular invoice, we have multiple sales people working. The reason we combine the invoice is becuase we are an exporter and often consolidate cargo for our customer to save them freight costs. How do I capture the contribution of each line item in the invoice to the sale so that I can tag them against a sales person. 

We are an exporter. So say we receive a 40 ft container worth of goods from a customer, we have sales persons working on multiple Purchase orders from the same customer since a single person cannot handle it along. So it makes it necessary for us to capture how much each sales person has contributed to the entire invoice.

I am open to suggestions in terms of any customizations, usage of Zoho Analytics etc.