Dynamic collaborations are the means by which a group of autonomous entities (possibly competing) collaborate to achieve a common objective by sharing resources that may be owned and managed both privately or jointly. Our focus in this paper is on controlling jointly owned shared data that is inherently ephemeral, as it does not exist outside the period of the collaboration. This paper explores the application of the Ephemerizer concept as a means to control the access to shared collaboration data. Towards this, we first define a service-oriented architecture Anitya1 that enables the development of a third party service for managing ephemeral data in dynamic collaborations. We then extend the pair wise secure communication protocol used in the Ephemerizer and propose three different multiparty secure group communication protocols for sharing collaboration data under the defined architecture. We also discuss the design, implementation, and evaluation of the architecture and protocols.