When multiple distributed parties work together and coordinate activities towards a common purpose, they have common plans, tasks and goals, while they do not share individual tasks, goals and domain expertise. Hence, they need to cooperate to organise individual activities in a way so that individual as well as common goals are achieved. Therefore, all the activities must be harmonised in a holistic framework of true collaborative state. Using observations of a case study in project planning and scheduling, analysis of this collaboration is classified into three levels of organisational, collective and individual. The focus of this paper is on interconnecting the second and the third levels. While a cognitive approach is applied to explore human interaction in decision-making, the relationship between individual and group praxis is studied using the concepts of Activity Theory (AT). In fact, collaborative scenarios are where we need to use both viewpoints for a smooth movement between the layers of studying joint activities. This framework can be used to support collaborative work.