Hi Shohag Mia 

The best is to use the Buyer plan (GESPOI), it allows to group multiple PR on stored product & non-stored products even from different receiving sites (as long as they are within the same company).

Else, you can use the grouping plan (FUNMPICKA) but this is only limited to stored products and grouping per receiving site.

Would you please provide any video about consolidating Multiple PR in single PO?