In this paper, we present an operator to model
interactions among objects. Our proposal allows a
variable number of participant objects in an interaction,
and this number will be fixed during the execution of the
model. This provides a very flexible interaction model
based on synchronous interactions among several
objects. Our interaction model is based on events and
allows a multiple-way communication among objects.
Concrete values of a communication are generated
through constraints which are imposed locally on each
participant object. The proposed interaction (and communication)
model is very versatile and can be used as
an abstract specification mechanism
