The activity area-based curriculum model (AACM) is used in the Finnish basic education to support pupils—most of whom have profound intellectual and multiple disabilities (PIMD)—who could benefit more from skills that advance independent life coping. Existing studies have concentrated mainly on the Individual Education Plan (IEP) goal-setting process for pupils with milder disabilities than PIMD and have consistently demonstrated significant barriers in the process. This study explores the collaborative IEP goal-setting process for pupils with the AACM. Sixty-five Finnish special education teachers using the AACM participated in the study. Semi-structured interviews were analysed with thematic network analysis. The groups involved in the IEP goal-setting process were divided into main and side mediators. The main mediators were described as significant collaborators with important knowledge of the pupil, while side mediators rarely participated in the process. The special education teachers appeared to be leading the collaboration and were positioned in the middle of the main and side mediators. Further research should focus on the implementation of parents’ collaborative positions. Furthermore, practices and methods should be developed to reinforce the positions of group home staff, special education teacher colleagues and pupils with the AACM or PIMD themselves.