Different 3D tele-immersive (3DTI) activities pose different prioritized requirements for application and network-level quality of service (QoS) to ensure a strong quality of experience (QoE) for participants. Some applications put heavy weight on audio quality, some consider higher quality for upper body video streams, and some seek very low end-to-end interactivity delay. In addition, a variation in streaming content may arise in the 3DTI space due to the participants' change in interests (e.g., view change). Therefore, there is a need for an adaptive multistream, multisite 3DTI session management strategy that is not only unobtrusive, but also optimizes prioritized QoS parameters in 3DTI content distribution based on user activity and content variation. To address this next generation session management problem, we revisit the design space of multistream and multisite 3DTI session layer. We present an evolutionary 3DTI session optimization approach using Open Session Management (OSM) architecture that uses a global view of participants and overlays network conditions to optimize QoS parameters. Experimental results with PlanetLab traces show that our optimization process is unobtrusive, and the optimized TI sessions provide higher satisfaction to the participants (in some cases up to 50% higher) compared to the current solutions in the 3DTI space.