Right then and there, during your critique. They obviously don't understand what you are saying. Misspell and mispronounce group members' names. Pick a scapegoat, someone whose skills, experience, politics, or creative output just isn't up to your standards. Disagree with everything this person says and hammer his fiction extra-hard, but keep him in the group at all costs.
Every joke needs a butt.
Require transportation to and from each meeting. This has the added advantage of making the actual reading of other peoples' material unnecessary. Never host a meeting. If it's absolutely necessary, make sure your kids are awake, the air conditioner's broken, and the refrigerator's empty. Serve decaf and tell everyone it's real.