Paradigms of object-oriented programming are attractive for the design of large distributed software. They notably provide a sound basis to develop applications that are easy to maintain and reuse. However, expressing concurrency in object-oriented languages raises some difficulties. For instance, integrating concurrency together with inheritance may lead to violate the encapsulation property of object-oriented programming. In this paper we present a new strongly-typed, concurrent object-oriented language, called Arche, that enables the development of reusable distributed software. The Arche language has been designed so as to keep all the benefits of the object paradigm. In particular, the Arche conditional synchronization mechanism is defined in such a way that synchronization constraints of an existing class can be specialized and reused. Furthermore, a mechanism that allows a larger scale synchronization, that is, involving more than just a pair of processes, is offered by supporting application of operations on a collection of objects. To our knowledge, such a facility has never been addressed in the framework of strongly-typed, concurrent object-oriented programming despite the ability to simply manage collection of peer objects it provides.