As it turns out, my resolution was a combination of using both files. Here are what my entries look like:
humanrec: jsmith, ajones, ltaylor
I had previously discovered that simply creating users on my linux box was not also generating the ability to receive email. In order to do so, I added entries into the virtusertable file. Apparently, by adding such an entry for an alias is also necessary. Thus, the user is not "unknown" by the virtusertable file and is then using the alias file to determine the recipients.