Tanja, I make the assumption that if I assign a task to a Team that someone from the Team (1 person) will accept and work on the task. If I specifically want more than one person to work on a task, then instead of assigning to a Team, I assign to those specific people. So, for my team, it's an assumption when assigning to a Team that only one person will accept to work on the task. If you want everyone to contribute, consider assiging to those individuals and not the Team.
We often have a task that we need everyone on the team to work on. For large teams, manually adding every individual is inefficient. We need a better approach to mass assign people to tasks. This seems like a great approach!