The purpose of this study was to elucidate conditions at all system levels in a specific health care service to develop practices for identification of children as relatives. An interactive research approach with the intention to create mutual learning between practice and research was used. The participating health care service cared for both clinic in- and outpatients with psychiatric disorders. Health care professionals from different system levels (micro, meso, macro) participated, representing different professions. At the first project meeting, it was obvious that there was no systematic approach to identify children as relatives. At the micro level, activities such as a pilot survey and an open house activity were carried out. At the meso level, it was discussed how to better support collaboration between units. At the management (macro) level, it was decided that all units should appoint at least one child agent, with the aim to increase collaboration throughout the whole health care service. To change focus, in this case from only parents to inclusion of children, is an important challenge faced by health care services when forced to incorporate new policies and regulations. The new regulations contribute to increased complexity in already complex organizations. This study highlights that such challenges are underestimated.