This set of muscles perform the same actions and are synergists.

Both latissimus dorsi and teres major perform adduction, extension and medial rotation of the glenohumeral joint. Pectoralis major and minor act on two different joints. Gluteus medius and maximus have similar actions but gluteus medius also flexes the coxal joint. Both supraspinatus and teres minor hold the glenohumeral head in the glenoid cavity, but that's the only similarity with their actions.