Abstract: The facility gives users of a telecommunications network access to services provided by agents. Call-directors receive the calls, groups of agents process them, and transit units serve as interfaces between the call-directors and the agents. First means select a transit unit for a call that has reached a call-director, as a function of a minimum cost obtained by comparing costs which are established for the various transit units. Second means select a processing group for a call that has reached a transit unit that was previously empty of calls, with selection being as a function of a minimum cost obtained by comparing costs established for the various processing roups. Third means select a transit unit for processing a call waiting in a transit unit as soon as an agent becomes available, as a function of a maximum cost obtained by comparing costs established for the various transit units.