There isn't an easy way to specify what to bind to.
Modify the source code, re-compile it.

Or just use a firewall. That's even easier.
I'm trying to set up a hidden service on tor, and I've copied the following into my torrc:
HiddenServiceDir /some/directory
HiddenServicePort 8333 127.0.0.1:8333
but now I'd like to make bitcoin bind only to 127.0.0.1:8333 whereas "netstat -lp" shows that it is listening on all interfaces. I haven't easily found how to specify this.
suggestions?