If you were doing a tasting with 150 people face to face you would split into groups of a reasonable number. How about you create a new topic for each set (probably not a Discourse group) of people? You could have people split by some market like the first letter of their name or similar. If you know ahead of time who will attend you could do assign them a priori.
If you used first letter of their user name you’d have some stats on how to guess what letters to use.