To answer your question downwind, many people can and regularly do talk on an HF freq at once. The freqs used in the Asian area are a case in point. Listen to 5658, 6556, 8842, 10066 for an idea what happens. It is possible to contact, say, MNL while SIN is working another station and both can pass their respective messages. It is good etiquette to wait till the freq is clear but on many that never happens. Thank Heavens for CPDLC!!
