A receptacle assembly for receiving and holding in place flexible containers in the upright position while the flexible containers are being transported on a conveyor. The receptacle assembly includes a guide supporting two supports, an adjustment mechanism, and a plurality of transport receptacles. Each transport receptacle includes two side supports, each of which are mounted on one of the supports. The supports are capable of being selectively displaced with respect to each other by operation of the adjustment mechanism, which allows the transport receptacle to be adjusted to receive and hold flexible containers of various sizes and configurations.