Field help (KACGGRP) 

This field is used to enter the accounting Group.
When an Item reference is entered, the group will automatically receive the group code specified in the item setup. It can be modified if the expense is not capitalized or not issued from the validation of a purchase invoice. 
In the case where the field associations are set up for the Expense object, the accounting group can define the values of different fields, including the account postings.