Can we have lines from multiple sales orders in one fulfillment set.

Problem Description: I have 3 orders with multiple lines with different line types.. I want to create a fulfillment set or a rule that can wait for all the lines in the three orders to get fulfilled and then be sent to invoicing. So basically the question is can we have fulfillment set created for multiple orders ar is it only for the lines in one single order?

Is there any other way to achieve this in order management.