Enact a new subrule to “Submissions”, called “Courier Submissions”:-

A Broker may make a Courier Submission, which consists of the name of a Broker (as the Recipient), and either the title of a piece of Art in their own Collection or an amount of Cash. The same Broker may make multiple Courier Submissions during a single round. Courier Submissions may be retracted by their submitter during the same round they were made in, by notifying the Collector of this, at which point they cease to be Courier Submissions.

Add a step after the third in “Starting a Round”:-

* For each valid Courier Submission made during the previous round: if it named a piece of Art which appears in the Collection of the Broker who made the Submission, move it to the Recipient’s Collection; if it named an amount of Cash and the Broker who made the Submission has that much Cash, move that much Cash from the Broker who made the Submission to the Recipient.