Thank you all very much for this incredibly helpful feedback! DEVONthink has exceeded my expectations in every regard, so I knew there had to an easier approach to this particular issue.
I had originally considered making tags of all the author’s names, as @BLUEFROG suggested, but the number of tags I already had in place started to feel a bit unwieldy. That’s when I tried this alternate route, which I see now was not correct. Somehow I missed that Aliases are meant for one document only, but that makes perfect sense now.
Thanks also for the suggestions about custom metadata fields and smart groups. These ideas open up a number of new possibilities for me.
DEVONthink is truly a masterpiece. I have a feeling I could spend years learning about its capabilities without ever discovering them all. My thanks to the developer and to all the helpful power users on this forum!