How to link Events while generating Draft Invoice

Hi,

We are doing R12 implementation from 11i (not upgrade patch,  complete re-implementation).  The requirement for data conversion is to bring all the 11i Events and create Draft Invoice and send to AR. Similarly bring all 11i Events >create Draft Revenue and send to GL.

Events>Draft Invoice>AR:

We are creating 11i Events in R12 with cutoff date. But when we run Generate Draft invoice, all these Billing Events gets clubbed into one big Draft invoice and gets into AR. We want to create Draft Invoice and link Event so that multiple Invoices can be created. We are using Client extension to Approve and Release Invoices.