First Message - Looking for wholesale suggestions

I am looking to better calculate my monthly sales by group. 1) Shopify Online Sales 2) Retailer Sales 3) Amazon

Currently - I enter my retailer orders manually in Shopify to keep track of when the payment is due as well as my sales and inventory. I am manually pulling reports by customer in Shopify to figure out which sales go to each group by a customer search. Then I have to pull my Cost of Goods the same way.

Any easier ways to do this?