Separate dialogue processes from decision-making processes. Set up small peer learning or support groups or a buddy system so that no one is working without a safe person or group with which to share ideas or problems. Be sure that these support groups have a way to feed information back to the larger group so problems can be addressed systemically. Set milestones so that all involved can be acknowledged for their successes. Breaking a large process into smaller milestones can make the whole thing less overwhelming.
Some people do prefer to work in isolation.
I submit that those individuals still have some responsibility to provide feedback and share their experience with others committed to the same change process. It is easy to underestimate how much our work affects others. If the last meeting causes you to dread the next meeting, then this workshop might be for you. Productive and participative meetings are not an accident. Whether a staff, department or committee meeting, there are some simple ways to ensure that your meetings will have an impact.