Multiple DC into one invoice for B2B credit customers.(grouping item wise)

example for the customer C1 transactions below

DC1 item1 10 qty price 100 value 1000

item2 5 qty price 100 value 500

DC2 item2 2 qty price 100 value 200

invoice should generate at the end of the month

item1 10qty price 100 value 1000

item2 7 qty price 100 value 700

total inv value should be 1700/-