The invention pertains to a method of connecting at least two containers for enabling a transfer of liquid from one container to the other container, comprising the steps of: a) Depositing a first cassette including at least a first container on a first tray. The first container has a plurality of connecting means. b) Depositing a second cassette including a second container on a second tray. The cassettes or the containers include a data storage means. c) The data are read by respective data reading means. d) The data are processed and it is verified whether they match each other. e1) In case of a negative result, the second cassette is removed and the steps from step b) onwards are repeated. e2) In case of a positive verification result, the containers are connected. f) Removing the second cassette. g) Repeating steps b) to f) a plurality of times.
