A computer-implemented method is described comprising: identifying a set of contacts and/or contact groups permitted to contact a user of a data processing device during a scheduled event in an electronic calendar; receiving a communication event from a first contact over a first communication channel; comparing the first contact against the identified set of contacts and/or contact groups permitted to contact the user; and notifying the user of the communication event during the scheduled event only if the first contact is in the set of contacts and/or contact groups.