3D Teleimmersive (TI) Networks enable collaborative interactive activities in the same virtual space. The geographically distributed multi-site nature of TIs, the heterogeneity and multi-modality of their I/O devices and the diversity of activities in these environments pose new challenges in designing networked I/O device management for TIs not addressed by existing systems. In this paper we describe Decima, a holistic virtualized I/O Management. Decima enables dynamic seamless and universal access and management to asymmetric Teleimmersive activities using a large scale of heterogeneous TI devices. Our experiments show that Decima is lightweight in terms of CPU overhead and end-to-end delay and scales well as the number of devices in the TI network increases.