The present invention concerns a method at a file server for sending more than one file to more than one receiver, comprising the steps of aggregating the files into a container, splitting the container into more than one packet, and transmitting the more than one packet to the more than one receiver, wherein, the reception of at least one packet of the container enables a receiver to request the reception of lost packets of the container. To this end, the method comprises the steps of receiving an indication of the number of consecutive lost packets of the container per the more than one receiver and adapting the size of the container, in function of the number of consecutive lost packets at the receivers.