Subinventory Expense Account overriding the Item Expense

Hello,

The issue that I am experiencing is that I have the following for an account set up:

01 Organization

8400 Department

3410 Expense Subaccount

My problem is, is that the last Expense Subaccount should be stemming from my Item Master, and the Department should come from my Subinventory. However when a Subinventory is chosen, the entire account associated with said Subivnentory is coming into the PO.

Is there some sort of setup that this overrides that last natural account?

Thanks,

-Justin