The task of carrying out humanitarian and peace-keeping missions by a high number of hardly collaborating and vaguely linked non-governmental organizations is a challenging problem. Collaborators, joined by a common goal, group into parties playing an active role in the mission. In the paper we have considered such groups of collaborators as alliance and coalition. On the account of the fact that some of the group members (agents) representing individual organizations may diagree to cooperate (share information and resources) with all the other agents but only with a selected number of them, we introduced the specific type of alliance called "restricted alliance". The paper focuses on the problem of coalition formation (coalition structure) with the agents of restricted alliance. The main attentions is paid to the issues of agents' activities at the stage of coalition structuring.