We present an instructional model involving a computer-supported collaborative learning environment, in which students from two conflicting groups collaboratively investigate an event relevant to their past using historical texts. We traced one enactment of the model by a group comprised of two Israeli Jewish and two Israeli Arab students. Our data sources included the texts participants wrote--pre-, post- and during the activity, jointly and individually--the transcripts of the e-discussion and reflections written after the activity. The setting enabled us to further our understanding of what collaboration means when students' voices do not converge. We examined whether the activity was productive in terms of learning, and the dynamics of collaboration within the milieu, especially the intersubjective meaning making. The e-discussion that was co-constructed by participants was a chain of disagreements. However, participants' reflections reveal that the group structure and the e-communication method were perceived as affording sensitive collaboration. Furthermore, a comparison between the individual texts, pre- and post- the group discussion, revealed that the activity was productive, since students moved from a one-sided presentation of the event to a more multi-sided representation. Based on the analysis of the e-discussion, we conclude that the setting provided students with opportunities to examine their voices in light of alternatives. We propose the term "fission" to articulate certain moments of intersubjectivity, where a crack is formed in one's voice as the Other's voice impacts it, and one's voice become more polyphonic.