Sub-Recipe Group assigns the sub-recipe to one of the groups you create under Settings > Kitchen Settings > Sub-Recipe Groups (e.g. Sauces, Marinades). Inactive groups still appear in the dropdown marked "(Inactive)". Priority Order is a 1-5 ranking (1 = high, 5 = low) used to order sub-recipes on kitchen prep reports (they're printed under a "Priority #" label). Both fields exist only on sub-recipes.