Loading Equipment Repair Costs into E1 without affecting G/L


We implemented E1 for our financials on 01/01/16 and are running 9.1 on servers, plus we have a homegrown application on our iSeries that outputs costs which we would like to load into E1 to update the repair costs on specific Equipment.
These costs been processed through the A/P application in E1, but are not assigned to Equipment because it is not known which piece of equipment the 'purchased product' will be used on and charged to.
The costs are also tracked in our iSeries application and when the 'purchased product' is used on a piece of Equipment in this application a detail record is written to a flat file charging the cost of the product to the piece of equipment it was put on.
Since the cost has already been processed through A/P and updated the proper 'Equipment Repair' G/L account in E1, we do not want to have the costs from the iSeries to update the G/L account again.

Is it possible to add Costs in E1 from a third party system, assigning it as Repair Cost to a piece of equipment, but not affecting G/L?
Or am I looking at this wrong and there is a proven solution?
The easiest and cleanest method would be to effectively put the 'purchased product' expense to an unallocated repair costs account on PO receipt in JDE. Then, when the costs are determined in your custom solution you can journal the costs into an allocated repair costs account in JDE with the equipment identifier information completed using the Z table interface.

The only issue you need to deal with is timing in terms of which financial period the journals occur in but basically you're just doing a cost reallocation.
Thank you Russell, I will review your suggestion with our financial people to see if it is workable and acceptable to them