In our work, an agent-based system supporting workers in an organization is centered around utilization of ontologically demarcated data. In this system, ontological matchmaking, understood as a way of establishing closeness between resources, is one of key functionalities. Specifically, it is used to autonomously provide recommendations to the user, who is represented by her/his personal agent. These recommendations specify, which among available resources are relevant / of interest to the worker. In this paper, we discuss our approach to measuring semantic closeness between ontologically demarcated information objects, while a Duty Trip Support application is used as a case study. General description of the algorithm is followed by a recommendation example based on support for a worker who is seeking advice in planning a duty trip.