Alec, Taylor,
Your replies imply that this is not possible.
The use of different port or address, dedicated only for incoming tor, is some workaround, but it has the obvious downside that if somebody manages to reach it and connect outside of tor, then the target application will perceive it as an incoming tor connection.
This is mitigated if using unix sockets at the cost of added complexity of managing filesystem permissions and only works on the same host and not on Windows. Some firewalls support maching by user, so one could setup a rule that only allows connections to the dedicated port from the tor user.
Alec, incoming tor connections do not have a "from onion address".
Thanks!