Repeater

I want to create two repeaters linked to a single table. For example, I have a transaction form, and within this form, there are sections for both the buyer and seller. I am using repeaters for both the buyer and seller, but they both point to the same table, "Contact." How can I map the relationships when creating and retrieving data, considering that the buyer and seller are both stored in the "Contact" table but are distinguished by a "type" field?