Hello Jason and welcome to the Cow Audio Forum.
If everyone’s sitting close together, I think the easiest solution would be a live boom op and one mic.
He/she would hang out in the middle and either tilt or shift left and right as needed.
This becomes more difficult if there’s a lot of extemporaneous talking and interrupting, but could still work.
Each person talking would ideally have the same level voice, but that doesn’t always happen. When it doesn’t, I park the mic over the quiet person and tilt to get the louder one from a distance. This is sometimes called “mixing with air.”
You might also put two locked down booms between 1 & 2 and 2 & 3 and split track them.
Three lavs and an automixer will also work, but probably won’t sound as good as one or two really good hyper/super caardioid boom mics.
Regards,
Ty Ford
Cow Audio Forum Leader
Want better production audio?: Ty Ford’s Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford’s Blog