I can't take the credit for it, as my husband figured it out for me. We're happy to share it, but we are not coders by any means - we just try stuff until it works.

My husband says that it isn't something simple that he can tell you to do - he had to insert a table in the message area of postlist.tmpl with its own definitions for cell number, table layout, border settings etc. If you just want the code he put in the postlist.php that's ok, but it would look funny without the modifications to the postlist.tmpl file. Plus he's still diddling with it.
Let me know if you still want it. Like I said, we are no experts, so it would be at your own risk.

Cheers!