Adding Transactions to Run Billing & Revenue

I am adding records into AC54 so that I have some expense to run Billing & Revenue.  The problem is that these expenses are already embedded with other expenses in interfaces into Lawson.  I cannot change my interfaces to exclude the portion of the expense that I want to run Billing and Revenue for.  Therefore, I am double booking the expense and want to reverse out the entries that I am making in AC54 after I run Billing & Revenue.  I do not know the best way to do this.