Need Advice - How to attribute a Vendor Credit to sales staff - commissions & sales incentives issue

Any advice or direction would be appreciated from the community. I'm trying to get our reporting in order before we bring our sales team into NetSuite (initial cutover was accounting only). Our company is issued vendor credits for sales commissions or as incentives by our vendors if sales goals are hit. Long story short, our vendors effectively pay us for work outside of our territory, and i need to attribute that credit as though its income to the sales person who's customer the work is done on.

Does anyone have a similar process, or ideas about how you could roll vendor credits into a sales report if they're stand alone (not tied to a vendor invoice) because the credits are issued for something other than a return... in my case, the vendor credits are issued in lieu of a payment.