SLA Invalid Account

We are using SLA with payables for shop floor destination POs. We are doing this because we do not use the Oracle accrual process and want the expense recognized at the time of invoice rather than receipt.  When we create accounting, if the account combination on the PO has become invalid, we end up posting to a suspense account in the General Ledger - so no error is generated. We would like to see an error message of some kind generated, but still allow the suspense posting. Does anyone have an idea of how we could accomplish this.

Thank you for any help you can provide.