A method for determining relationship data associated with application programs in a messaging system, comprising the steps of: responsive to at least one first message event sending a message from a first application to a first destination and at least one second message event retrieving, by a second application, the message from a second destination, intercepting message data associated with the message; analysing the intercepted message data in accordance with one or more rules in order to find one or more message parameters; and in response to finding the one or more message parameters, identifying the first message event and identifying the second message event, determining a relationship associated with the first application and the second application. An apparatus and computer program element for determining such relationship data are also provided.