I downloaded the source code at commerce.ssh.com, which is free for non-commercial use. It compiled right out of the box, and was installed in /usr/local, so my original OpenSSH is still intact in /usr. Now I can access remote just as easily from local1 as from local2.
I am somewhat confused, though, since I had supposed OpenSSH and SSH to be completely compatible. If for some reason you would like to run /usr/local/sbin/sshd instead of /usr/sbin/sshd, you could easily accomplish this by changing the relevant line in /System/Library/StartupItems/SSH/SSH.

