Split Item Groups in Bills

Enhancement Description: We have added the ability to split item groups within a bill into multiple groups. This enhancement is especially useful for businesses like Miracle Ear, where a single customer may manage multiple franchise locations. For instance, a customer handling 9 locations can now split costs among 9 accounting classes within a single bill. This eliminates the need to manage and approve multiple bills, simplifying the process and improving efficiency by keeping all splits visible in a single bill.