A PMHNP is conducting family therapy with a 16-year-old adolescent presenting with anorexia nervosa and her parents. During the session, the mother answers every question directed at the daughter, corrects the daughter's statements, and physically leans forward between the therapist and the daughter. The father sits silently at the periphery. When the daughter attempts to speak, the mother interrupts with 'What she means is...' The PMHNP, using structural family therapy, asks the mother and father to discuss together how they will support their daughter's recovery, while instructing the daughter to observe without speaking. During this conversation, the mother repeatedly turns to the daughter for validation, and the father defers to the mother on all decisions. Which structural family therapy concept and technique is the therapist employing?