How do you join a contact between two stations using the PACTOR protocol?

PACTOR is a robust, error-correcting digital protocol used primarily for sending data and emails over HF frequencies, such as with the Winlink network. It relies on an Automatic Repeat Request (ARQ) handshaking process to ensure 100% data integrity between the sender and receiver. Because the protocol fundamentally requires this synchronized, direct handshake between the two communicating stations, a PACTOR connection is strictly limited to two stations at a time. It is a point-to-point protocol by design. It is impossible for a third station to 'break in' or join an existing PACTOR data stream. Options suggesting sending broadcast packets, transmitting a steady carrier, or sending a NAK code are incorrect because the ARQ protocol simply does not support multi-station conference connections.