Scenario
Your company receives multiple in-season orders from a big wholesale customer. The customer requests you to ensure the different orders are shipped together so that they can be received in a consolidated way in the customer’s distribution center or store.
Pack Separate - Ship Together (PSST)

With this functionality, you can create grouping rules and use them to group items that need to ship together based on the customer's business rules.
Document types are to be activated for PSST handling in IMG
Sales orders: Sales and Distribution → Sales → Sales Documents → Sales Document Header → Maintain Sales Document Types per Sales Area for Fashion Management.
STOs: Materials Management → Purchasing → Purchase Order → Maintain Stock Transport Order Types per Sales Area for Fashion Mgmt.

Document types are to be activated for PSST handling in IMG:
Sales orders: Sales and Distribution → Sales → Sales Documents → Sales Document Header → Maintain Sales Document Types per Sales Area for Fashion Management.
STOs: Materials Management → Purchasing → Purchase Order → Maintain Stock Transport Order Types per Sales Area for Fashion Mgmt.
Transaction for grouping rule creation is RFM_PSST_GRA
Transaction to create PSST group numbers is RFM_PSST_MONITOR. It is also used to monitor PSST groups.