TM maintain their own list of Agents. But they will also link a listing to an agent using the REA Licence Code.
You can enter the Agent REA licence code in Office Live > Staff profile – details tab, scroll about have way down to the REA Licence box.
This is the mechanism that TM users to be able to display all sold listings for an Agent across multiple agencies. Because the REA licence code for an Agent doesn't change as they move from one agency to another.