Multiple Independent Stakeholders

We have a current project involving fundamentally enmeshed yet mutually exclusive stakeholders all sharing spaces, costs, etc. Obviously we anticipate that each stakeholder will submit its claim schedule, as opposed to its real schedule, as we proceed (including the team we are tasked with overseeing). No one wants to accept responsibility for managing a "Site Master Schedule", nor do they want to expose their respective schedule at any more than the most summary level. However, it is our task to assess the program schedule for our team and the risk associated both within their schedule and in relation to the other stakeholders’ schedules.

Any ideas on how to attack this?

Also, since I’m already here, anyone worked on any Calatrava projects previously? I’d like to engage in a discussion outside the forum if so.