Setting Up a Waterfall in Clay for Partial Data Enrichment

Hi! I have a question. Suppose I have a dataset with 10 rows, and email IDs are already available for 5 of them. I want to set up a waterfall in Clay so that credits are used only to enrich the 5 rows where email IDs are missing. However, for validation, I’d like to include all 10 records—both the existing and enriched ones. How can I achieve this setup?