as the use case specification (individual task) is made for each task, does it mean the use case diagram has 6 use cases (1 for each task)? Because as I know correctly, the use case specification is made for each use case.
The use case diagram should cover all tasks that your group has signed up for. However, whether it should be represented as 6 diagrams or combined as 1 diagram, you should make your own choice.
as the use case specification (individual task) is made for each task, does it mean the use case diagram has 6 use cases (1 for each task)? Because as I know correctly, the use case specification is made for each use case.