The paper presents an agent-based model for the explicit representation of groups of pedestrians in a crowd. The model is the result of a multidisciplinary research (CRYSTALS project) where multicultural dynamics and spatial and socio-cultural relationships among individuals are considered as first class elements for the simulation of crowd of pilgrims taking to the annual pilgrimage towards Makkah. After an introduction of advantages of Multi-Agent System approach for pedestrian dynamics modelling, a formal description of the model is proposed. The scenario in which the model was developed and some examples about modelling heterogeneous groups of pedestrians are described.
