I've got a Purchase Order - User Event script and an Item Receipt - User Event script. I want to re-run the PO UE script when the IR is created or edited to reflect a new total number of items received on the PO. Right now I've got the IR UE script loading and saving the PO record, because I thought it would cause the beforeSubmit on the PO UE script to trigger, but it's not. What's the best way to handle this? I'd rather not duplicate the entire function from the PO on the IR.

Since it is a UE script, it wont trigger the other UE script even if it is in a different record. What I have done in the past is to call a Suitelet to do the load and save, that should trigger your other UE