No, of course there isn't a visible receiver address.

You have a list of peers, P1,...,PN, every second, at a specific pre-decided time, slightly fuzzed to avoid timing stuff, you send a message to each of them. If you don't put one in, it's a dummy message chosen at random and encrypted. But if you have a message, you send that at the appointed time.

Consequently, from the outside of the system, from the PoV of someone who does not have the keys, its behaviour is indistinguishable from a system where no one is sending any messagess at all.