A method apparatus and system for assembling meeting data to update a calendar database are provided, based on meeting request data including meeting invitees and a given time period, and further based on availability data from at least one availability database. Availability data associated with each meeting invitee is processed to determine availability of each meeting invitee during the given time period, and determine at least one unavailable invitee that is unavailable during the given time period. Reporting structure data is processed, from a reporting structure, to determine a respective alternate invitee for each at least one unavailable invitee. Availability data associated with each alternate invitee is processed to determine whether each alternate invitee is available during the given time period. If so, meeting data is assembled, for storage in the calendar database, the meeting data including respective identifiers of meeting invitees available during the given time period and of each alternate invitee, and meeting data is caused to be stored in the calendar database.