A hot runner injection molding apparatus (10) includes hot runner nozzles (20), a movable frame (30) that can be displaced between at least two positions relative to a plurality of mold cavities (24), each cavity having a mold gate (27). Valve pins (32) associated with the hot runner nozzles (20) are individually coupled to the movable frame (30) by a decouplable connector (36, 60). Disengagement devices (40) associated with the valve pins are activated to decouple any associated valve pin (32) from the movable frame (30). A control system (52) is used to activate the disengagement devices (40). In some instances a blocking element (42) is also activated to lock any valve pin at the mold gate or close to the mold gate. Control system (52) is further used to operate the blocking element (42). Disengagement devices (40) and the blocking elements (42) can be the same or different.