A good client, will look at the combination of kind 10050 relay lists. If alice and bob both have a DM relay in common Auth to it with your key. Then, if bob is sending to alice's extra relays, then auth with the ephemeral key that was generated and send the event without making any reqs... (after auth handshake). Seems ez 😁 You won't be keeping that connection anyway it was one time use for sending.