I wonder if the following Luther quote has any significance for participating in ministerial alliances, or "community" Thanksgiving worship services?
I abhor the assembly of evildoers and refuse to sit with the wicked. Psalm 26:5
We should have nothing to do with evildoers and wicked people. David said, “ I have nothing but hatred for them” (Psalm 139:22). The author of Psalm 1 praises believers who avoid them: “Blessed is the man who does not walk in the counsel of the wicked or stand in the way of sinners or sit in the seat of mockers” (v. 1). If you spend too much time with false teachers, you will eventually share in their false doctrine, lies, and errors. If you play with tar, you’re going to get dirty.
From Martin Luther, Faith Alone: A Daily Devotional, James C. Galvin, general editor.